Hey. I read a thread recently about this same idea. Try the search tab and you might find it. As well as removing the 'guts' remove any metal screws, you can glue it back together with aquarium silicone. It might be an idea to fill it with wet sand or stones/gravels to weigh it down. Just because it's plastic, doesn't meat it will be safe. You will need to make sure it is air-tight. There is a product you can use for sealing it, like the stuff the TV show 'Tanked' use for their creations. I think it might be called eproxy(not sure??)....In gonna do a video game theme tank. I was gonna put a couple old controllers on the bottom. Besides removing the guts. Do I have to treat them it's just plastic.