Once your guinea pigs are used to being handled, they’ll enjoy being brushed. This is only really necessary in long-haired varieties, although all types enjoy it. Always brush their hair in the direction it grows - having their fur hair pushed in a different direction can be a little uncomfortable for them.
If your guinea pig has short hair and is in good health then you don’t need to do any serious grooming, as long as you give them a little brush over at fairly regular intervals. Guinea pigs are clean creatures, and will do most of their own grooming themselves. However, if you have a long-haired guinea pig then they’ll probably need daily grooming in order to keep their coats tangle-free and clear of any mess that they’re likely to pick up in their day-to-day life. If your long-haired guinea pig isn’t going to be shown, you might want to consider cutting their hair to a more manageable length.
Alpaca Guinea Pigs reporting for grooming!
Short- and long-haired varieties alike will need to have their rumps cleaned to remove he residue from their grease gland. Guinea pigs use this gland to mark their territory, but the grease is sticky and needs to be cleaned off their fur. Use a bit of mild washing up liquid, guinea pig shampoo or a grease dissolver fit for human skin. Leave it on the soiled area for a few minutes and then rinse off.