diff --git a/lib/bcoin/mtx.js b/lib/bcoin/mtx.js
index 8248151e..cc72e187 100644
--- a/lib/bcoin/mtx.js
+++ b/lib/bcoin/mtx.js
@@ -200,6 +200,7 @@ MTX.prototype.addOutput = function addOutput(options, value) {
     output.value = value;
   } else {
     output.fromOptions(options);
+    assert(output.value >= 0);
   }
 
   this.outputs.push(output);
diff --git a/lib/bcoin/output.js b/lib/bcoin/output.js
index 9296bdf8..0171e683 100644
--- a/lib/bcoin/output.js
+++ b/lib/bcoin/output.js
@@ -48,7 +48,6 @@ Output.prototype.fromOptions = function fromOptions(options) {
 
   if (options.value) {
     assert(utils.isNumber(options.value));
-    assert(options.value >= 0);
     this.value = options.value;
   }
 
diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index 92e7798a..f9d877a6 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -56,8 +56,18 @@ Witness.prototype.__defineSetter__('length', function(length) {
  */
 
 Witness.prototype.fromOptions = function fromOptions(options) {
-  this.items = options.items || options;
-  assert(Array.isArray(this.items));
+  var items = options.items;
+
+  if (!items)
+    items = options;
+
+  assert(Array.isArray(items));
+
+  // Duplicate:
+  // items = items.slice();
+
+  this.items = items;
+
   return this;
 };
 
@@ -1123,23 +1133,23 @@ Script.prototype.fromOptions = function fromOptions(options) {
     raw = options.raw;
   }
 
-  if (code)
+  if (code) {
     code = Script.parseArray(code);
+    // Duplicate:
+    // code = code.slice();
+  }
+
+  if (!raw)
+    raw = Script.encode(code);
+  else if (!code)
+    code = Script.decode(raw);
+
+  assert(Array.isArray(code));
+  assert(Buffer.isBuffer(raw));
 
   this.raw = raw;
   this.code = code;
 
-  if (!this.raw) {
-    assert(this.code);
-    this.raw = Script.encode(this.code);
-  } else if (!this.code) {
-    assert(this.raw);
-    this.code = Script.decode(this.raw);
-  }
-
-  assert(Buffer.isBuffer(this.raw));
-  assert(Array.isArray(this.code));
-
   return this;
 };
 
@@ -4358,6 +4368,8 @@ Script.encode = function encode(code, writer) {
   var p = new BufferWriter(writer);
   var i, op;
 
+  assert(Array.isArray(code));
+
   for (i = 0; i < code.length; i++) {
     op = code[i];
 
@@ -4406,6 +4418,8 @@ Script.parseArray = function parseArray(code) {
   var out = [];
   var i, op;
 
+  assert(Array.isArray(code));
+
   if (code[0] instanceof Opcode)
     return code;
 
diff --git a/test/script-test.js b/test/script-test.js
index 8be549c7..2525c0a5 100644
--- a/test/script-test.js
+++ b/test/script-test.js
@@ -365,7 +365,6 @@ describe('Script', function() {
           coin._hashSequence = null;
           coin._hashOutputs = null;
 
-          delete input.redeem;
           delete input._address;
           delete output._address;
         }
diff --git a/test/tx-test.js b/test/tx-test.js
index a8635943..1bcc537c 100644
--- a/test/tx-test.js
+++ b/test/tx-test.js
@@ -38,7 +38,6 @@ function clearCache(tx, nocache) {
   if (tx instanceof bcoin.script) {
     if (!nocache)
       return;
-    tx.redeem = null;
     return;
   }
 
@@ -61,8 +60,6 @@ function clearCache(tx, nocache) {
   for (i = 0; i < tx.inputs.length; i++) {
     input = tx.inputs[i];
     input._address = null;
-    input.script.redeem = null;
-    input.witness.redeem = null;
   }
 
   for (i = 0; i < tx.outputs.length; i++) {