I honestly don't have a problem putting the PT out of my mind when I watch the originals- but then I've only seen the PT films once (except for TPM which I got roped into seeing twice). I can't even remember much about AOTC except that I hated it - LOL!
I'm sure that has a lot to do with the fact that I was a SW fan for so many years before the prequels came out, but I think that the PT will eventually fade from your memory as long as you make an effort never to watch them again.