Piggies have their peeing corners; hay trays are usually the biggest toiletting area as well as the sleeping areas. You can use pupp pads in those areas if you have just a few guinea pigs. I use old cut-up washable padded incontinence mattress covers for the bedding areas and cheap cotton towels in the other areas as underlay.
Poo you get all over the place; you notice them much more than other bedding and need to poo patrol once or twice daily.
Please read our guides and tips on fleece. It also helps investing on good quality micro or polar fleece, which wicks away best. Make sure that you have any trace of surface sealing softener washed out before you use fleece, never use softener when washing and never overfill the machine (your fleece comes out stinking to high heaven). I would also strongly recommend to wash your fleece at a higher temperature (60-90 C) from time to time to get on top of any build-up of bacteria. The commercial antibacterial in wash products just won't do it. Fleece shrinks when you wash at higher temperatures, so you need to allow about 10 in for that.