Over the years, I lost close friends I never thought I would, who simply could not relate to my new found frumkite (ok, it was new found many years ago now). But I have retained a small group of those non-religious friends who are not the least bit interested in anything religious while obviously gaining many new frum friends through the years. Actually, I gained an entire community. It’s very seldom that non religious people have access to a community to be a part of.
If you want to dispose of those old friends really quickly, just proselytize to them your faith. That ought to do the trick. (If there was a winking emoticon, I’d use it here)