diff --git a/lib/speakingurl.js b/lib/speakingurl.js
index 4a62bc0..4e2ee50 100644
--- a/lib/speakingurl.js
+++ b/lib/speakingurl.js
@@ -1460,7 +1460,8 @@
 
         if (typeof opts === 'object') {
             maintainCase = opts.maintainCase || false;
-            customReplacements = (opts.custom && typeof opts.custom === 'object') ? opts.custom : customReplacements;
+            const customIsObject = typeof opts.custom === 'object'
+            customReplacements = (opts.custom && customIsObject) ? opts.custom : customReplacements;
             truncate = (+opts.truncate > 1 && opts.truncate) || false;
             uricFlag = opts.uric || false;
             uricNoSlashFlag = opts.uricNoSlash || false;
@@ -1511,6 +1512,8 @@
 
                 if (v.length > 1) {
                     r = new RegExp('\\b' + escapeChars(v) + '\\b', 'gi');
+                } else if (customIsObject && /^[0-9]$/.test(v)) {
+                    r = null
                 } else {
                     r = new RegExp(escapeChars(v), 'gi');
                 }
diff --git a/test/test-custom.js b/test/test-custom.js
index aea5ef0..959b98f 100644
--- a/test/test-custom.js
+++ b/test/test-custom.js
@@ -16,6 +16,12 @@ describe('getSlug with custom replacement', function () {
             })
             .should.eql('буу');
 
+        getSlug('top 100 waterfalls', {
+                custom: ['.']
+            })
+            .should.eql('top-100-waterfalls');
+
+
         getSlug('[nodejs]', {
                 custom: {
                     '[': '[',