You can, but they need to be disinfected in case they are carrying respiratory or tummy bugs. It is quite an elaborate process with wooden things, but easier with ceramic and plastic. The metal parts of the cage can be cleaned, but parts with worn paint would need extra soaking, scrubbing, rinsing and drying.
. Anything plastic or ceramic can just be washed with dishwashing liquid and rinsed. Or to disinfect them, just spray them with pet-safe disinfectant and leave a few minutes and rinse off. Any smooth wood items can just cleaned similarly, or you can give them a light spray with disinfectant and then rinse and leave them to air. Any barkwood items like natural bark houses, shelves or bendy stick bridges, are harder to de-odorise/disinfect. You can bake them in the oven but to be honest I would probably bin bendy stick bridges as they are hard to get fully disinfected in the gaps.
thanks everyone.
If you soak in boiling water it lifts off in pieces using a paper scrapper when I had guinea pigs their wee corner needed doing weekly dried and brown so I did the job in the bath while they were out in their runI’ve always wondered about this…all my female hamsters have had a wee corner which over time does get a bit dried up with dust from bedding, which is hard to get off. Would you still be able to reuse a cage in this instance