We have the "Zapper" on our line (I hate to think how long ago we bought it) and it gets rid of most of our nuisence calls. The few we get I hang up on -- and we are on the "do not call list". I inform any charities that if they want my money they can send me the information in the mail (and if they ask for the address, I tell them they should have it since they have the phone number). I never give out my cc# to a random charity.