diff --git a/src/main/java/net/seanomik/energeticstorage/objects/ESDrive.java b/src/main/java/net/seanomik/energeticstorage/objects/ESDrive.java
index a3435e5..1c74c5f 100644
--- a/src/main/java/net/seanomik/energeticstorage/objects/ESDrive.java
+++ b/src/main/java/net/seanomik/energeticstorage/objects/ESDrive.java
@@ -122,7 +122,7 @@ public class ESDrive implements Cloneable {
             // The item is contained, then update the amount.
             if (Utils.containsSimilarItem(new ArrayList<>(items.keySet()), item, true)) {
                 int amount = (int) items.values().toArray()[Utils.indexOfSimilarItem(new ArrayList<>(items.keySet()), item)] + item.getAmount();
-                Utils.removeSimilarItem(items, item);
+                items = Utils.removeSimilarItem(items, item);
                 items.put(item, amount);
             } else {
                 items.put(item, item.getAmount());
@@ -138,12 +138,12 @@ public class ESDrive implements Cloneable {
         // If there isn't enough items stored to take out the requested amount, then just take out all that we can.
         int foundItemAmount = (int) items.values().toArray()[Utils.indexOfSimilarItem(new ArrayList<>(items.keySet()), item)];
         if (foundItemAmount - item.getAmount() < 1) {
-            Utils.removeSimilarItem(items, item);
+            items = Utils.removeSimilarItem(items, item);
             item.setAmount(foundItemAmount);
         } else {
             int newAmount = foundItemAmount - item.getAmount();
 
-            Utils.removeSimilarItem(items, item);
+            items = Utils.removeSimilarItem(items, item);
             items.put(item, newAmount);
         }
 
diff --git a/src/main/java/net/seanomik/energeticstorage/utils/Utils.java b/src/main/java/net/seanomik/energeticstorage/utils/Utils.java
index b6b6e20..ce6163d 100644
--- a/src/main/java/net/seanomik/energeticstorage/utils/Utils.java
+++ b/src/main/java/net/seanomik/energeticstorage/utils/Utils.java
@@ -66,8 +66,21 @@ public class Utils {
         return false;
     }
 
-    public static void removeSimilarItem(Map<ItemStack, Integer> itemStacks, ItemStack item) {
-        itemStacks.entrySet().removeIf(entry -> removeAmountFromLore(entry.getKey()).isSimilar(item));
+    public static Map<ItemStack, Integer> removeSimilarItem(Map<ItemStack, Integer> itemStacks, ItemStack item) {
+        removeAmountFromLore(item);
+        // Doing this does not work. So we're gonna have to make some ugly code...
+        // The reason it doesn't work is due to Spigot implementing its own `hashCode` implementation,
+        // which Java's Iterator#remove method relies on and regenerates the hashCode when removing.
+        //itemStacks.entrySet().removeIf(entry -> removeAmountFromLore(entry.getKey()).isSimilar(item));
+
+        Map<ItemStack, Integer> items = new HashMap<>();
+        for (Map.Entry<ItemStack, Integer> entry : itemStacks.entrySet()) {
+            if (!removeAmountFromLore(entry.getKey()).isSimilar(item)) {
+                items.put(entry.getKey(), entry.getValue());
+            }
+        }
+
+        return items;
     }
 
     public static int indexOfSimilarItem(List<ItemStack> itemStacks, ItemStack item) {