You're supposed to tear it down, clean it out and start over. Does everyone do that....No. But you are now gathering a rather large collection. It is more important than ever that you follow very strict quarantine procedures... and that means taking fewer risks. There is no way to truly "clean" a biological environment like a viv. Will it kill the new inhabitants...probably not....but who know. Would you put your newly acquired Glass Frogs in there, that you've waited two years for? Probably not, because you wouldn't want to take the risk. Doing something like that is a risk....only you can decide if its worth it.