You could always invite them in for a dip... if they say, "What?"
explain that you were offering them acid - then begin to offer them all kinds of drugs and ask if they want to cut their wrists with you in the shower and then remind them that it's perfectly normal and that you do this all the time.
I think it's just because of the shock value that I like to do things like this.
To me, while educating a religion is a fine idea, I don't think showing up at my doorstep repeatedly in an attempt to convert me by fear saying that when the lord doth come I shall be cast into the pits of fire because I don't believe in the same thing you believe in is taking it to the next level of a$$holism.