Shake the bedding over a sink or outside to avoid getting your home dirty. Offer your guinea pig a litter pan filled with straw where they can use the bathroom. Change the straw daily. This will encourage your pet to avoid soiling the fleece.
If you have other laundry to do, you can throw in items of similar color and texture into the machine while washing fleece bedding.
Cedar bedding Clay-based bedding Sawdust Newspaper