diff --git a/SabreTools.Filtering/Cleaner.cs b/SabreTools.Filtering/Cleaner.cs
index 5e383030..18120627 100644
--- a/SabreTools.Filtering/Cleaner.cs
+++ b/SabreTools.Filtering/Cleaner.cs
@@ -123,7 +123,7 @@ namespace SabreTools.Filtering
         /// <summary>
         /// Logging object
         /// </summary>
-        private Logger logger = new Logger();
+        private readonly Logger logger = new Logger();
 
         #endregion
 
@@ -140,6 +140,10 @@ namespace SabreTools.Filtering
             ExcludeMachineFields ??= new List<MachineField>();
             ExcludeDatItemFields ??= new List<DatItemField>();
 
+            // If the list is null or empty, just return
+            if (fields == null || fields.Count == 0)
+                return;
+
             foreach (string field in fields)
             {                
                 // If we don't even have a possible field name
@@ -186,6 +190,10 @@ namespace SabreTools.Filtering
             MachineFilter ??= new MachineFilter();
             DatItemFilter ??= new DatItemFilter();
 
+            // If the list is null or empty, just return
+            if (filters == null || filters.Count == 0)
+                return;
+
             foreach (string filterPair in filters)
             {
                 (string field, string value, bool negate) = ProcessFilterPair(filterPair);
diff --git a/SabreTools.Test/Filtering/CleanerPopulationTests.cs b/SabreTools.Test/Filtering/CleanerPopulationTests.cs
new file mode 100644
index 00000000..fee5cad9
--- /dev/null
+++ b/SabreTools.Test/Filtering/CleanerPopulationTests.cs
@@ -0,0 +1,169 @@
+using System.Collections.Generic;
+
+using SabreTools.Filtering;
+using Xunit;
+
+namespace SabreTools.Test.Filtering
+{
+    public class CleanerPopulationTests
+    {
+        [Fact]
+        public void PopulateExclusionNullListTest()
+        {
+            // Setup the list
+            List<string> exclusions = null;
+
+            // Setup the cleaner
+            var cleaner = new Cleaner();
+            cleaner.PopulateExclusionsFromList(exclusions);
+
+            // Check the exclusion lists
+            Assert.Empty(cleaner.ExcludeDatHeaderFields);
+            Assert.Empty(cleaner.ExcludeMachineFields);
+            Assert.Empty(cleaner.ExcludeDatItemFields);
+        }
+
+        [Fact]
+        public void PopulateExclusionEmptyListTest()
+        {
+            // Setup the list
+            List<string> exclusions = new List<string>();
+
+            // Setup the cleaner
+            var cleaner = new Cleaner();
+            cleaner.PopulateExclusionsFromList(exclusions);
+
+            // Check the exclusion lists
+            Assert.Empty(cleaner.ExcludeDatHeaderFields);
+            Assert.Empty(cleaner.ExcludeMachineFields);
+            Assert.Empty(cleaner.ExcludeDatItemFields);
+        }
+
+        [Fact]
+        public void PopulateExclusionHeaderFieldTest()
+        {
+            // Setup the list
+            List<string> exclusions = new List<string>
+            {
+                "header.datname",
+            };
+
+            // Setup the cleaner
+            var cleaner = new Cleaner();
+            cleaner.PopulateExclusionsFromList(exclusions);
+
+            // Check the exclusion lists
+            Assert.Single(cleaner.ExcludeDatHeaderFields);
+            Assert.Empty(cleaner.ExcludeMachineFields);
+            Assert.Empty(cleaner.ExcludeDatItemFields);
+        }
+
+        [Fact]
+        public void PopulateExclusionMachineFieldTest()
+        {
+            // Setup the list
+            List<string> exclusions = new List<string>
+            {
+                "machine.name",
+            };
+
+            // Setup the cleaner
+            var cleaner = new Cleaner();
+            cleaner.PopulateExclusionsFromList(exclusions);
+
+            // Check the exclusion lists
+            Assert.Empty(cleaner.ExcludeDatHeaderFields);
+            Assert.Single(cleaner.ExcludeMachineFields);
+            Assert.Empty(cleaner.ExcludeDatItemFields);
+        }
+
+        [Fact]
+        public void PopulateExclusionDatItemFieldTest()
+        {
+            // Setup the list
+            List<string> exclusions = new List<string>
+            {
+                "item.name",
+            };
+
+            // Setup the cleaner
+            var cleaner = new Cleaner();
+            cleaner.PopulateExclusionsFromList(exclusions);
+
+            // Check the exclusion lists
+            Assert.Empty(cleaner.ExcludeDatHeaderFields);
+            Assert.Empty(cleaner.ExcludeMachineFields);
+            Assert.Single(cleaner.ExcludeDatItemFields);
+        }
+    
+        [Fact]
+        public void PopulateFilterNullListTest()
+        {
+            // Setup the list
+            List<string> filters = null;
+
+            // Setup the cleaner
+            var cleaner = new Cleaner();
+            cleaner.PopulateFiltersFromList(filters);
+
+            // Check the filters
+            Assert.NotNull(cleaner.MachineFilter);
+            Assert.NotNull(cleaner.DatItemFilter);
+        }
+
+        [Fact]
+        public void PopulateFilterEmptyListTest()
+        {
+            // Setup the list
+            List<string> filters = new List<string>();
+
+            // Setup the cleaner
+            var cleaner = new Cleaner();
+            cleaner.PopulateFiltersFromList(filters);
+
+            // Check the filters
+            Assert.NotNull(cleaner.MachineFilter);
+            Assert.NotNull(cleaner.DatItemFilter);
+        }
+
+        [Fact]
+        public void PopulateFilterMachineFieldTest()
+        {
+            // Setup the list
+            List<string> filters = new List<string>
+            {
+                "machine.name:foo",
+                "!machine.name:bar",
+            };
+
+            // Setup the cleaner
+            var cleaner = new Cleaner();
+            cleaner.PopulateFiltersFromList(filters);
+
+            // Check the filters
+            Assert.Contains("foo", cleaner.MachineFilter.Name.PositiveSet);
+            Assert.Contains("bar", cleaner.MachineFilter.Name.NegativeSet);
+            Assert.NotNull(cleaner.DatItemFilter);
+        }
+
+        [Fact]
+        public void PopulateFilterDatItemFieldTest()
+        {
+            // Setup the list
+            List<string> filters = new List<string>
+            {
+                "item.name:foo",
+                "!item.name:bar"
+            };
+
+            // Setup the cleaner
+            var cleaner = new Cleaner();
+            cleaner.PopulateFiltersFromList(filters);
+
+            // Check the filters
+            Assert.NotNull(cleaner.MachineFilter);
+            Assert.Contains("foo", cleaner.DatItemFilter.Name.PositiveSet);
+            Assert.Contains("bar", cleaner.DatItemFilter.Name.NegativeSet);
+        }
+    }
+}
\ No newline at end of file
diff --git a/SabreTools.Test/SabreTools.Test.csproj b/SabreTools.Test/SabreTools.Test.csproj
index b1017c22..6afdd39e 100644
--- a/SabreTools.Test/SabreTools.Test.csproj
+++ b/SabreTools.Test/SabreTools.Test.csproj
@@ -7,6 +7,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\SabreTools.Core\SabreTools.Core.csproj" />
+    <ProjectReference Include="..\SabreTools.Filtering\SabreTools.Filtering.csproj" />
     <ProjectReference Include="..\SabreTools.IO\SabreTools.IO.csproj" />
     <ProjectReference Include="..\SabreTools.Skippers\SabreTools.Skippers.csproj" />
   </ItemGroup>