You cant boil them or put them in peroxide it will make them crack and break. Best thing is just to wash them with antibacterial soap and hot water. (I've been a piercer for 3 years and I found that out the hard way)
jebus lol, i dont remember. what ever size they start you off with. 16 maybe? i still have mine in and i haven't changed the size sense i got it done and they all would fit.