I will be the first to say that being pulled out of a warm bath on a Friday night after a hard day at work by people you really don't want to talk to isn't the most pleasant thing. But there are some things you can do to make things a bit easier with the 'Elders'.
One: If you really don't want them there, put up a 'No Soliciting' sign -- they are required by law (and manners) to not bother you. This will also keep Jehovah's Witness, Hari Krishnas and other Faith Peddlers away. Along with the Fuller Brush Man.
Two: If you do answer the door, don't be an ass about it. Let them say their piece then politely tell them that you're not interested -- they're used to this and, believe it or not, they won't think any less of you. Slamming the door in their faces or screaming obscenities is not the way towards enlightenment.
Above all, never forget that, even though they look like walking billboards for the Men's Warehouse Clothing Store, they are simply decent people and if you treat them well, they'll treat you the same way regardless of whether you want to listen to them spout or not. Purchase does not increase the odds of winning.