You shouldn't ever put cloth of any sort in with a guinea pig, they don't nest and they will nibble on it and can possibly die from the strings, or get tangled in it etc.
Also cedar is a no no. It produces a smell when wet that can kill them. Not to mention it's usually sold in chips that are not soft and can cause bumblefoot. You can use pine safely as long as you get rid of the dust part, and pick out the stray sticks so it's soft. I used chicken bedding (pine) from a feed store and it cost $8, if that, for a years worth (every week I dumped it and hot water washed the cage).
2 dogs, Buddy and Diesel
5 Male Betta's, (Special) Ed, Mushu, Forrest Gump, Azeroth, and Onyx
12 Purple Pincher Hermit Crabs
2 Ecuadorian Hermit Crabs