diff --git a/SabreTools.Core/Filter/FilterRunner.cs b/SabreTools.Core/Filter/FilterRunner.cs
index 1aec568f..28cd3aca 100644
--- a/SabreTools.Core/Filter/FilterRunner.cs
+++ b/SabreTools.Core/Filter/FilterRunner.cs
@@ -15,6 +15,11 @@ namespace SabreTools.Core.Filter
         /// </summary>
         public readonly FilterObject[] Filters;
 
+        /// <summary>
+        /// Cached item type names for filter selection
+        /// </summary>
+        private readonly string[] _datItemTypeNames = TypeHelper.GetDatItemTypeNames();
+
         public FilterRunner(FilterObject[] filters)
         {
             Filters = filters;
@@ -54,7 +59,7 @@ namespace SabreTools.Core.Filter
             foreach (var filter in Filters)
             {
                 // Skip filters not applicable to the item
-                if (filter.Key.ItemName == "item" && Array.IndexOf(TypeHelper.GetDatItemTypeNames(), itemName) == -1)
+                if (filter.Key.ItemName == "item" && Array.IndexOf(_datItemTypeNames, itemName) == -1)
                     continue;
                 else if (filter.Key.ItemName != "item" && filter.Key.ItemName != itemName)
                     continue;
diff --git a/SabreTools.DatFiles/ItemDictionary.cs b/SabreTools.DatFiles/ItemDictionary.cs
index 1aeb5eb5..e281d6d3 100644
--- a/SabreTools.DatFiles/ItemDictionary.cs
+++ b/SabreTools.DatFiles/ItemDictionary.cs
@@ -203,19 +203,23 @@ namespace SabreTools.DatFiles
         /// </summary>
         public void ClearMarked()
         {
-            foreach (string key in SortedKeys)
+            string[] keys = [.. SortedKeys];
+#if NET452_OR_GREATER || NETCOREAPP
+            Parallel.ForEach(keys, Core.Globals.ParallelOptions, key =>
+#elif NET40_OR_GREATER
+            Parallel.ForEach(keys, key =>
+#else
+            foreach (var key in keys)
+#endif
             {
-                // Get the unfiltered list
-                List<DatItem> list = GetItemsForBucket(key, filter: false);
-
-                foreach (DatItem datItem in list)
-                {
-                    if (datItem.GetBoolFieldValue(DatItem.RemoveKey) != true)
-                        continue;
-
-                    RemoveItem(key, datItem);
-                }
+                var list = GetItemsForBucket(key, filter: true);
+                RemoveBucket(key);
+                list.ForEach(item => AddItem(key, item));
+#if NET40_OR_GREATER || NETCOREAPP
+            });
+#else
             }
+#endif
         }
 
         /// <summary>