Can you put a rabbit into a another rabbits used cage?
Yes, provided the first rabbit wasn't sick. If it was, or you're not sure, spray the cage with Lysol or a similar disinfectant, then rinse it with clean water. Don't forget the rinse.
Yea if it's clean.
sure you can Only after its been cleaned
Yes, just wash it with hot water.
Can people live in another people's used house?..yes