diff --git a/lib/script/stack.js b/lib/script/stack.js
index 49e70890..18e62f9c 100644
--- a/lib/script/stack.js
+++ b/lib/script/stack.js
@@ -515,7 +515,6 @@ Stack.fromString = function fromString(str, enc) {
 };
 
 Stack.toNum = function toNum(item, minimal, limit) {
-  assert(Buffer.isBuffer(item));
   return ScriptNum.decode(item, minimal, limit);
 };
 
@@ -525,13 +524,7 @@ Stack.fromNum = function fromNum(num) {
 };
 
 Stack.toInt = function toInt(item, minimal, limit) {
-  assert(Buffer.isBuffer(item));
-
   const num = Stack.toNum(item, minimal, limit);
-
-  if (!num)
-    return -1;
-
   return num.getInt();
 };