diff --git a/src/neo/Network/RPC/RpcServer.cs b/src/neo/Network/RPC/RpcServer.cs
index 5649cce92f..e2137d517c 100644
--- a/src/neo/Network/RPC/RpcServer.cs
+++ b/src/neo/Network/RPC/RpcServer.cs
@@ -111,7 +111,7 @@ public void Dispose()
 
         private JObject GetInvokeResult(byte[] script, IVerifiable checkWitnessHashes = null)
         {
-            ApplicationEngine engine = ApplicationEngine.Run(script, checkWitnessHashes, extraGAS: MaxGasInvoke);
+            using ApplicationEngine engine = ApplicationEngine.Run(script, checkWitnessHashes, extraGAS: MaxGasInvoke);
             JObject json = new JObject();
             json["script"] = script.ToHexString();
             json["state"] = engine.State;
diff --git a/src/neo/Wallets/AssetDescriptor.cs b/src/neo/Wallets/AssetDescriptor.cs
index dca0b10b25..46a80a0f5c 100644
--- a/src/neo/Wallets/AssetDescriptor.cs
+++ b/src/neo/Wallets/AssetDescriptor.cs
@@ -19,7 +19,7 @@ public AssetDescriptor(UInt160 asset_id)
                 sb.EmitAppCall(asset_id, "name");
                 script = sb.ToArray();
             }
-            ApplicationEngine engine = ApplicationEngine.Run(script, extraGAS: 3_000_000);
+            using ApplicationEngine engine = ApplicationEngine.Run(script, extraGAS: 3_000_000);
             if (engine.State.HasFlag(VMState.FAULT)) throw new ArgumentException();
             this.AssetId = asset_id;
             this.AssetName = engine.ResultStack.Pop().GetString();
diff --git a/src/neo/Wallets/Wallet.cs b/src/neo/Wallets/Wallet.cs
index 52fa839b16..954923df8f 100644
--- a/src/neo/Wallets/Wallet.cs
+++ b/src/neo/Wallets/Wallet.cs
@@ -132,7 +132,7 @@ public BigDecimal GetBalance(UInt160 asset_id, params UInt160[] accounts)
                 sb.EmitAppCall(asset_id, "decimals");
                 script = sb.ToArray();
             }
-            ApplicationEngine engine = ApplicationEngine.Run(script, extraGAS: 20000000L * accounts.Length);
+            using ApplicationEngine engine = ApplicationEngine.Run(script, extraGAS: 20000000L * accounts.Length);
             if (engine.State.HasFlag(VMState.FAULT))
                 return new BigDecimal(0, 0);
             byte decimals = (byte)engine.ResultStack.Pop().GetBigInteger();