diff --git a/src/mailgo.js b/src/mailgo.js
index 0dd1f0a..602f904 100644
--- a/src/mailgo.js
+++ b/src/mailgo.js
@@ -641,6 +641,10 @@ const composedPath = el => {
 // validate an array of emails
 const validateEmails = arr => arr.every(validateEmail);
 
+// TODO
+// clean a telephone number (removes +, - ...)
+const cleanTel = tel => tel;
+
 // copy of a string
 const copyToClipboard = str => {
   let el = document.createElement("textarea");