[dremd]

Toilet paper (aka cellulose) filters actually do more to prevent acid formation than any other filter.
Cellulose has the ability to suck up lots of water and keep it out of your engine.
Try dropping a roll of TP in the toilet, you will see what I mean.
That said it still has a finite ability to hold water.
Big issue with TP filters is typically that they plug very easily with contaminates vs other bypass filters, that said, filter elements are cheap, very available, and many believe that they filter better than anything.

Again, if you are interested, checkout bobistheoilguy.com forums, tons of very knoleageable people there.