Clean it how? Worried about pathogens? 1:10 bleach solution at most, but honestly unless you're super worried about aiptasia I wouldn't bother with that, maybe if you had seriously nasty hair algae/briopsis that's an option with acrylic, but I wouldn't with glass for fear of the silicone hanging onto the bleach, for glass just razor blade everything out. To remove coraline or other calcium based gunk, vinegar is probably easiest, citric acid solution is another option (you buy the crystals and make it yourself) or diluted muriatic acid if you're careful and have serious built up stuff on it.