You still provide paper nesting material as well
. Plain white toilet paper torn into strips is safest- a pile of that and the pouch it and take it to the heat to build or rebuild it. But they will also take the odd bit of paper substrate/bedding as well for their nest. The strips are easier for nest building though and it keeps its shape better. Hamsters also really enjoy the paper bedding as it’s soft. I use Fitch which is recycled food grade paper. Looks very similar to Kaytee clean and cosy but comes in bulk 10kg bags (about the size of a child’s beanbag chair).