I've personally never had them, but I've read that rubbing ripe banana peel on the effected area and then taping a small bit of a banana peel with duct tap, with the inside facing the wart for 24hrs. Then using a cottonball soaked in apple cidar vinegar and leaving it on for a few hours. Continuing to alternate the two until its gone works like a charm.
But truly, it's a sign that you're immune system is low. Eating healthy and including herbal suppliments to increase your immune system is best long term cure.