diff --git a/lib/bcoin/lowlevelup.js b/lib/bcoin/lowlevelup.js
index 37796b47..8eb65582 100644
--- a/lib/bcoin/lowlevelup.js
+++ b/lib/bcoin/lowlevelup.js
@@ -423,7 +423,7 @@ VERSION_ERROR = 'Warning:'
   + ' format has changed drastically. If you want to dump your'
   + ' data, downgrade to your previous version first. If you do'
   + ' not think you should be seeing this error, post an issue on'
-  + ' the repo.'
+  + ' the repo.';
 
 /*
  * Expose
diff --git a/lib/bcoin/mempool.js b/lib/bcoin/mempool.js
index bb6cd278..90582f9c 100644
--- a/lib/bcoin/mempool.js
+++ b/lib/bcoin/mempool.js
@@ -652,7 +652,6 @@ Mempool.prototype.has = function has(hash, callback) {
 
 Mempool.prototype.addTX = function addTX(tx, callback, force) {
   var self = this;
-  var flags = constants.flags.STANDARD_VERIFY_FLAGS;
   var lockFlags = constants.flags.STANDARD_LOCKTIME_FLAGS;
   var hash = tx.hash('hex');
   var ret = {};
diff --git a/lib/bcoin/rbt.js b/lib/bcoin/rbt.js
index efb16fe8..ab931cd6 100644
--- a/lib/bcoin/rbt.js
+++ b/lib/bcoin/rbt.js
@@ -663,9 +663,6 @@ RBT.prototype.put = function put(key, value, options, callback) {
     options = null;
   }
 
-  if (!options)
-    options = {};
-
   this.insert(key, value);
 
   return utils.nextTick(callback);
@@ -684,9 +681,6 @@ RBT.prototype.del = function del(key, options, callback) {
     options = null;
   }
 
-  if (!options)
-    options = {};
-
   this.remove(key);
 
   return utils.nextTick(callback);
diff --git a/lib/bcoin/sigcache.js b/lib/bcoin/sigcache.js
index afe75468..47fbc225 100644
--- a/lib/bcoin/sigcache.js
+++ b/lib/bcoin/sigcache.js
@@ -43,7 +43,7 @@ function SigCache(size) {
  */
 
 SigCache.prototype.add = function add(hash, sig, key) {
-  var index, key;
+  var i, k;
 
   if (this.size === 0)
     return;
@@ -51,10 +51,10 @@ SigCache.prototype.add = function add(hash, sig, key) {
   this.valid[hash] = new SigCacheEntry(sig, key);
 
   if (this.keys.length === this.size) {
-    index = Math.floor(Math.random() * this.keys.length);
-    key = this.keys[index];
-    delete this.valid[key];
-    this.keys[index] = hash;
+    i = Math.floor(Math.random() * this.keys.length);
+    k = this.keys[i];
+    delete this.valid[k];
+    this.keys[i] = hash;
   } else {
     this.keys.push(hash);
   }