Helllllllllllllllllp!!!!! bleach!!!!!!!!!!?

ok so i got a shell with paint all over it and i wanted to put it in my tank with convicts. so my sister says to bleach it over night , so i did. so wen i go the shell later i boiled and washed it with vlean water and boiled it and washed it over abd over for about a 30 mins than i smelld it can i can small somthing but im not sure if its bleach i can only smell it bearly.ANWAYS can i put it in my tank?