diff --git a/README.md b/README.md
index b924805..48db483 100644
--- a/README.md
+++ b/README.md
@@ -259,6 +259,12 @@ public class CustomizedMaskedLogs
     [LogMasked(ShowFirst = 3, ShowLast = 3)]
     public string? ShowFirstAndLastThreeAndDefaultMaskInTheMiddle { get; set; }
 
+    /// <summary>
+    /// 123456789 results in "123456789", no mask applied
+    /// </summary>
+    [LogMasked(ShowFirst = -1, ShowLast = -1)]
+    public string? ShowFirstAndLastInvalidValues { get; set; }
+
     /// <summary>
     /// 123456789 results in "123***789"
     /// </summary>
@@ -278,7 +284,7 @@ public class CustomizedMaskedLogs
     public string? ShowFirstAndLastThreeAndCustomMaskInTheMiddlePreservedLengthIgnored { get; set; }
 }
 ```
-<sup><a href='/src/Destructurama.Attributed.Tests/MaskedAttributeTests.cs#L8-L127' title='Snippet source file'>snippet source</a> | <a href='#snippet-customizedmaskedlogs' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/Destructurama.Attributed.Tests/MaskedAttributeTests.cs#L8-L133' title='Snippet source file'>snippet source</a> | <a href='#snippet-customizedmaskedlogs' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 ## 7. Masking a string property with regular expressions
diff --git a/src/Destructurama.Attributed.Tests/AttributedDestructuringTests.cs b/src/Destructurama.Attributed.Tests/AttributedDestructuringTests.cs
index 8802c3e..64f5624 100644
--- a/src/Destructurama.Attributed.Tests/AttributedDestructuringTests.cs
+++ b/src/Destructurama.Attributed.Tests/AttributedDestructuringTests.cs
@@ -83,6 +83,8 @@ public void AttributesAreConsultedWhenDestructuring()
         props["ScalarAnyway"].LiteralValue().ShouldBeOfType<NotAScalar>();
         props["Struct1"].LiteralValue().ShouldBeOfType<Struct1>();
         props["Struct2"].LiteralValue().ShouldBeOfType<Struct2>();
+        props["StructReturningNull"].LiteralValue().ShouldBeNull();
+        props["StructNull"].LiteralValue().ShouldBeNull();
 
         var str = sv.ToString();
         str.Contains("This is a username").ShouldBeTrue();
@@ -152,6 +154,12 @@ public class Customized
         public Struct1 Struct1 { get; set; }
 
         public Struct2 Struct2 { get; set; }
+
+        [LogAsScalar(isMutable: true)]
+        public StructReturningNull StructReturningNull { get; set; }
+
+        [LogAsScalar(isMutable: true)]
+        public StructReturningNull? StructNull { get; set; }
     }
 
     public class UserAuthData
@@ -174,4 +182,10 @@ public struct Struct2
         public int SomeProperty { get; set; }
         public override string ToString() => "BBB";
     }
+
+    public struct StructReturningNull
+    {
+        public int SomeProperty { get; set; }
+        public override string ToString() => null!;
+    }
 }
diff --git a/src/Destructurama.Attributed.Tests/MaskedAttributeTests.cs b/src/Destructurama.Attributed.Tests/MaskedAttributeTests.cs
index 567ee1d..fc53f6f 100644
--- a/src/Destructurama.Attributed.Tests/MaskedAttributeTests.cs
+++ b/src/Destructurama.Attributed.Tests/MaskedAttributeTests.cs
@@ -105,6 +105,12 @@ public class CustomizedMaskedLogs
     [LogMasked(ShowFirst = 3, ShowLast = 3)]
     public string? ShowFirstAndLastThreeAndDefaultMaskInTheMiddle { get; set; }
 
+    /// <summary>
+    /// 123456789 results in "123456789", no mask applied
+    /// </summary>
+    [LogMasked(ShowFirst = -1, ShowLast = -1)]
+    public string? ShowFirstAndLastInvalidValues { get; set; }
+
     /// <summary>
     /// 123456789 results in "123***789"
     /// </summary>
@@ -359,6 +365,25 @@ public void LogMaskedAttribute_Shows_First_NChars_And_Last_NChars_Replaces_Value
         props["ShowFirstAndLastThreeAndDefaultMaskInTheMiddlePreservedLength"].LiteralValue().ShouldBe("123*456");
     }
 
+    [Test]
+    public void LogMaskedAttribute_With_Invalid_Values_Should_Return_Value_As_Is()
+    {
+        // [LogMasked(ShowFirst = -1, ShowLast = -1)]
+        // -> "123456789", no mask applied
+        var customized = new CustomizedMaskedLogs
+        {
+            ShowFirstAndLastInvalidValues = "123456789"
+        };
+
+        var evt = DelegatingSink.Execute(customized);
+
+        var sv = (StructureValue)evt.Properties["Customized"];
+        var props = sv.Properties.ToDictionary(p => p.Name, p => p.Value);
+
+        props.ContainsKey("ShowFirstAndLastInvalidValues").ShouldBeTrue();
+        props["ShowFirstAndLastInvalidValues"].LiteralValue().ShouldBe("123456789");
+    }
+
     [Test]
     public void LogMaskedAttribute_Shows_First_NChars_And_Last_NChars_Then_Replaces_All_Other_Chars_With_Custom_Mask()
     {
diff --git a/src/Destructurama.Attributed.Tests/ReplacedAttributeTests.cs b/src/Destructurama.Attributed.Tests/ReplacedAttributeTests.cs
index 614cf30..b2d2f47 100644
--- a/src/Destructurama.Attributed.Tests/ReplacedAttributeTests.cs
+++ b/src/Destructurama.Attributed.Tests/ReplacedAttributeTests.cs
@@ -32,6 +32,12 @@ public class CustomizedRegexLogs
     /// </summary>
     [LogReplaced(REGEX_WITH_VERTICAL_BARS, "***|$2|****")]
     public string? RegexReplaceFirstThird { get; set; }
+
+    /// <summary>
+    /// LogReplaced works only for string properties.
+    /// </summary>
+    [LogReplaced("does not matter", "does not matter")]
+    public int RegexReplaceForInt { get; set; }
 }
 
 [TestFixture]
@@ -134,4 +140,20 @@ public void LogReplacedAttribute_Replaces_First_And_Third()
         props.ContainsKey("RegexReplaceThird").ShouldBeTrue();
         props["RegexReplaceThird"].LiteralValue().ShouldBe("123|456|***");
     }
+
+    [Test]
+    public void LogReplacedAttribute_Should_Work_Only_For_String_Properties()
+    {
+        var customized = new CustomizedRegexLogs
+        {
+            RegexReplaceForInt = 42,
+        };
+
+        var evt = DelegatingSink.Execute(customized);
+
+        var sv = (StructureValue)evt.Properties["Customized"];
+        var props = sv.Properties.ToDictionary(p => p.Name, p => p.Value);
+
+        props.ContainsKey("RegexReplaceForInt").ShouldBeFalse();
+    }
 }
diff --git a/src/Destructurama.Attributed/Attributed/AttributedDestructuringPolicy.cs b/src/Destructurama.Attributed/Attributed/AttributedDestructuringPolicy.cs
index bbb8d74..6dbebc6 100644
--- a/src/Destructurama.Attributed/Attributed/AttributedDestructuringPolicy.cs
+++ b/src/Destructurama.Attributed/Attributed/AttributedDestructuringPolicy.cs
@@ -68,25 +68,27 @@ private static IEnumerable<PropertyInfo> GetPropertiesRecursive(Type type)
 
     private CacheEntry CreateCacheEntry(Type type)
     {
-        var classDestructurer = type.GetCustomAttribute<ITypeDestructuringAttribute>();
+        static T GetCustomAttribute<T>(PropertyInfo propertyInfo) => propertyInfo.GetCustomAttributes().OfType<T>().FirstOrDefault();
+
+        var classDestructurer = type.GetCustomAttributes().OfType<ITypeDestructuringAttribute>().FirstOrDefault();
         if (classDestructurer != null)
             return new(classDestructurer.CreateLogEventPropertyValue);
 
         var properties = GetPropertiesRecursive(type).ToList();
         if (!_options.IgnoreNullProperties && properties.All(pi =>
-            pi.GetCustomAttribute<IPropertyDestructuringAttribute>() == null
-            && pi.GetCustomAttribute<IPropertyOptionalIgnoreAttribute>() == null))
+            GetCustomAttribute<IPropertyDestructuringAttribute>(pi) == null
+            && GetCustomAttribute<IPropertyOptionalIgnoreAttribute>(pi) == null))
         {
             return CacheEntry.Ignore;
         }
 
         var optionalIgnoreAttributes = properties
-            .Select(pi => new { pi, Attribute = pi.GetCustomAttribute<IPropertyOptionalIgnoreAttribute>() })
+            .Select(pi => new { pi, Attribute = GetCustomAttribute<IPropertyOptionalIgnoreAttribute>(pi) })
             .Where(o => o.Attribute != null)
             .ToDictionary(o => o.pi, o => o.Attribute);
 
         var destructuringAttributes = properties
-            .Select(pi => new { pi, Attribute = pi.GetCustomAttribute<IPropertyDestructuringAttribute>() })
+            .Select(pi => new { pi, Attribute = GetCustomAttribute<IPropertyDestructuringAttribute>(pi) })
             .Where(o => o.Attribute != null)
             .ToDictionary(o => o.pi, o => o.Attribute);
 
diff --git a/src/Destructurama.Attributed/Attributed/LogMaskedAttribute.cs b/src/Destructurama.Attributed/Attributed/LogMaskedAttribute.cs
index 6caaafc..c2b90f0 100644
--- a/src/Destructurama.Attributed/Attributed/LogMaskedAttribute.cs
+++ b/src/Destructurama.Attributed/Attributed/LogMaskedAttribute.cs
@@ -53,15 +53,16 @@ private object FormatMaskedValue(string val)
         if (string.IsNullOrEmpty(val))
             return PreserveLength ? val : Text;
 
-        if (ShowFirst == 0 && ShowLast == 0)
+        return (ShowFirst, ShowLast) switch
         {
-            if (PreserveLength)
-                return new string(Text[0], val.Length);
-
-            return Text;
-        }
+            (0, 0) => PreserveLength ? new string(Text[0], val.Length) : Text,
+            ( > 0, 0) => ShowOnlyFirst(),
+            (0, > 0) => ShowOnlyLast(),
+            ( > 0, > 0) => ShowFirstAndLast(),
+            _ => val
+        };
 
-        if (ShowFirst > 0 && ShowLast == 0)
+        string ShowOnlyFirst()
         {
             var first = val.Substring(0, Math.Min(ShowFirst, val.Length));
 
@@ -73,10 +74,9 @@ private object FormatMaskedValue(string val)
                 mask = new(Text[0], val.Length - ShowFirst);
 
             return first + mask;
-
         }
 
-        if (ShowFirst == 0 && ShowLast > 0)
+        string ShowOnlyLast()
         {
             var last = ShowLast > val.Length ? val : val.Substring(val.Length - ShowLast);
 
@@ -90,7 +90,7 @@ private object FormatMaskedValue(string val)
             return mask + last;
         }
 
-        if (ShowFirst > 0 && ShowLast > 0)
+        string ShowFirstAndLast()
         {
             if (ShowFirst + ShowLast >= val.Length)
                 return val;
@@ -104,8 +104,6 @@ private object FormatMaskedValue(string val)
 
             return first + (mask ?? Text) + last;
         }
-
-        return val;
     }
 
     /// <inheritdoc/>
diff --git a/src/Destructurama.Attributed/Util/AttributeFinder.cs b/src/Destructurama.Attributed/Util/AttributeFinder.cs
deleted file mode 100644
index 6b5cc29..0000000
--- a/src/Destructurama.Attributed/Util/AttributeFinder.cs
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright 2018 Destructurama Contributors, Serilog Contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-using System.Reflection;
-
-namespace Destructurama.Util;
-
-internal static class AttributeFinder
-{
-    public static T GetCustomAttribute<T>(this Type typeInfo) =>
-        typeInfo.GetCustomAttributes().OfType<T>().FirstOrDefault();
-
-    public static T GetCustomAttribute<T>(this PropertyInfo propertyInfo) =>
-        propertyInfo.GetCustomAttributes().OfType<T>().FirstOrDefault();
-}
diff --git a/src/Destructurama.Attributed/Util/CacheEntry.cs b/src/Destructurama.Attributed/Util/CacheEntry.cs
index b1033b1..114df3b 100644
--- a/src/Destructurama.Attributed/Util/CacheEntry.cs
+++ b/src/Destructurama.Attributed/Util/CacheEntry.cs
@@ -17,7 +17,7 @@
 
 namespace Destructurama.Util;
 
-internal struct CacheEntry
+internal readonly struct CacheEntry
 {
     public CacheEntry(Func<object, ILogEventPropertyValueFactory, LogEventPropertyValue> destructureFunc)
     {