For this i'm not really sure but my advice for rebuildables is not to leave it unattended for a long period of time say 1 week. Previously, i had one and left it together with my carto for 2 weeks. As mentioned earlier, the carto vapes fine but when i vaped on the rebuildable it had a metalic taste. Not sure if it's the atty or the mesh that's causing this (was using a metal tank) though.