If you're worried about bleach toxicity, you could use vinegar and baking soda instead. I once got a cracked 50gal fish tank from Craigslist that was really dirty; like they had just taken the fish out and dumped out the water. I was able to clean it fairly easily with a spray bottle of 50% white vinegar, and for the tough spots I sprinkled a bit of baking soda. The fizzing reaction helps lift some of the more difficult grime. If you are more interested in disinfe3cting though, I would stick with the bleach. Like the others have said, it should be fine as long as you rinse well.