I get the rodipet cork logs - they have them the right size and shape for a hamster and hamster cage. Trouble is the shipping from Germany is about £8 extra and delivery isn't that quick. Some cork logs are very dirty. They should be just dry and dusty and just need a wash really. I just rinse them in hot water, use a nail brush to scrub any bits that look a bit grungy, let them dry, then I put them in the freezer for a week. I haven't had much success with baking them. I agree about taking that one back.
Others may have suggestions for where else you could get them. These are the rodipet ones. I get the large one but the medium is ok too. The large one is taller so I use it as a ramp under a shelf.
It might be better to get one you can see first maybe.
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