No. The digestion vessels must not be left assembled for extended periods of time (e.g. overnight). If digestion vessels are left assembled for extended periods of time, the O-rings in the vessel bottom assemblies will deform and future integrity could be compromised. If digestion vessels have been left assembled overnight, disassemble and allow to reshape for an hour or use another vessel bottom assembly base. It is very important to thoroughly clean the digestion vessels and vessel bottom assemblies after use. Use water, and NOT ethanol or acetone, as final rinse solution.