Step1: ignore it
On the phone, by email, by sms, on the Facebook chat, do not answer him anymore. Sticky men tend to think that the slightest attention you give them is a sign of interest. They imagine that they still have all their chances with you. The radio silence is an excellent remedy to put an end to these reveries.
Step 2: Play the card of the "franchise"
If, despite your indifference, your pretender comes back to the charge, a discussion is necessary. Find an objective excuse where he does not feel downgraded which will allow him to say that he can do nothing. It will leave more easily than if you find yourself in passionate relationships.
Several excuses to choose from: you go around the world in a week; you are still in love with your ex and are not ready for a new relationship; you already have a boyfriend and you are getting married next month.
Step 3: be firm
He still does not understand? It is high time you put them on the "i" but always avoid falling into passionate relationships. Impose and explain to him coldly and calmly that you are not interested and he is not your type. No is no !
You do not have to see him or call him to do this. A sms or a mail are very effective because they allow to better rationalize the situation. This is not cowardice, just a survival reflex!
Injured in his pride, your pot of glue should not bother you anymore. If he gets angry (classic reaction), do not answer (see step 1). It will run out on its own and you will finally have peace!