diff --git a/src/main/kotlin/xyz/alexcrea/cuanvil/listener/AnvilResultListener.kt b/src/main/kotlin/xyz/alexcrea/cuanvil/listener/AnvilResultListener.kt
index 7f9ef676..b9170804 100644
--- a/src/main/kotlin/xyz/alexcrea/cuanvil/listener/AnvilResultListener.kt
+++ b/src/main/kotlin/xyz/alexcrea/cuanvil/listener/AnvilResultListener.kt
@@ -214,10 +214,10 @@ class AnvilResultListener : Listener {
         val recipe = result.recipe!!
 
         // We remove what should be removed
-        if (rightItem != null) {
-            if (recipe.rightItem == null) return false// in case it changed
+        if (!rightItem.isAir) {
+            if (recipe.rightItem.isAir) return false// in case it changed
 
-            rightItem.amount -= amount * recipe.rightItem!!.amount
+            rightItem!!.amount -= amount * recipe.rightItem!!.amount
             view.setItem(ANVIL_INPUT_RIGHT, rightItem)
         }
 
diff --git a/src/main/kotlin/xyz/alexcrea/cuanvil/recipe/AnvilCustomRecipe.kt b/src/main/kotlin/xyz/alexcrea/cuanvil/recipe/AnvilCustomRecipe.kt
index fd079c3a..1cd2b616 100644
--- a/src/main/kotlin/xyz/alexcrea/cuanvil/recipe/AnvilCustomRecipe.kt
+++ b/src/main/kotlin/xyz/alexcrea/cuanvil/recipe/AnvilCustomRecipe.kt
@@ -176,8 +176,8 @@ class AnvilCustomRecipe(
         CustomAnvil.verboseLog("Left item passed !")
 
         // we don't know if right item can be
-        if (rightItem == null) { // null test
-            if (item2 != null) return false
+        if (rightItem.isAir) { // null test
+            if (!item2.isAir) return false
         } else {
             val rightSimilar = rightItem!!.isSimilar(item2)
             CustomAnvil.verboseLog("Right similar: $rightSimilar")
diff --git a/src/main/kotlin/xyz/alexcrea/cuanvil/util/CustomRecipeUtil.kt b/src/main/kotlin/xyz/alexcrea/cuanvil/util/CustomRecipeUtil.kt
index 058b25ad..b8a1907a 100644
--- a/src/main/kotlin/xyz/alexcrea/cuanvil/util/CustomRecipeUtil.kt
+++ b/src/main/kotlin/xyz/alexcrea/cuanvil/util/CustomRecipeUtil.kt
@@ -4,6 +4,7 @@ import io.delilaheve.CustomAnvil
 import org.bukkit.inventory.ItemStack
 import xyz.alexcrea.cuanvil.config.ConfigHolder
 import xyz.alexcrea.cuanvil.recipe.AnvilCustomRecipe
+import xyz.alexcrea.cuanvil.util.MaterialUtil.isAir
 import kotlin.math.min
 
 object CustomRecipeUtil {
@@ -32,7 +33,7 @@ object CustomRecipeUtil {
         return if(recipe.exactCount) {
             if(leftItem.amount != recipe.leftItem!!.amount){
                 0
-            }else if(rightItem != null && rightItem.amount != recipe.rightItem!!.amount){
+            }else if(!rightItem.isAir && rightItem!!.amount != recipe.rightItem!!.amount){
                 0
             }else{
                 1
@@ -43,7 +44,7 @@ object CustomRecipeUtil {
             val resultItem = recipe.resultItem!! // we know exist as the recipe was returned to us
             val maxResultAmount = resultItem.maxStackSize/resultItem.amount
             val maxLeftAmount = leftItem.amount/recipe.leftItem!!.amount
-            val maxRightAmount = if(rightItem == null){ maxLeftAmount } else{ rightItem.amount/recipe.rightItem!!.amount }
+            val maxRightAmount = if(rightItem.isAir){ maxLeftAmount } else{ rightItem!!.amount/recipe.rightItem!!.amount }
 
             CustomAnvil.verboseLog("resultItem: $resultItem, maxResultAmount: $maxResultAmount, maxLeftAmount: $maxLeftAmount, maxRightAmount: $maxRightAmount")