What type of line is it that you want to clean?
For the better S.A. and Rio lines, the S.A./3M cleaning pads work great. They take a minute layer of finish off and expose a brand new, slick surface. For those lines (S.A. with AST, Rio with XS) the dry, slick finish you get is all you need, really. Being dry it doesn't collect dirt and pond scum as much as some treatments either.
If your line is stained or hasn't been treated in a while, if ever, running them through a clean towel with warm, soapy water a few times then rinse with clen water. Use soap and not detergent, detergent can leach the plasticizors (I use and was recommended Ivory bar soap)
If all else fails, simply use what the manufacturer recommends. It really doesn't cost that much and goes a long, long way.
I used to dump the line in a sink or tub to clean but got frustrated with the snags and snarls I always seemed to get. Now I pace an area stripping off line and laying it on the floor. I usually use up two rooms and a hallway, I then run the line through the cloths while walking the length of the line. No snags and it gives the line a chance to relax and uncoil. Just be sure the cats are locked in another room!
As for Armorall, it's not worth the risk. From everything I'm told and have read, not only is it water soluable and does not last long on the line, it isn't formulated for fly lines and several people have said it ruined their fly line. It's funny how in the link Freda provided that guys friend in Vancouver 'invented' using Armorall. Yeah.... him and 10,000 other people who didn't have anything else handy!