I have paid down my credit cards to zero and my inclination is to stick them in a drawer and forget about them! However, it has occurred to me that, if I use them and pay them in full each moth, my credit score might increase! Which was should I go? I would like to increase my credit score prior to refinancing my mortgage. Thanks for your help!

I would continue to use them, maybe pay the balances over 2-3 months, rather than pay them off each month.

That will do more to help raise your score.

Agreed, just as long as you pay them off, and not miss any payments!