Is there a trick from keeping a RTV or sealant tube from hardening?

[Brandon Sinclair]

I have trouble with any RTV (black, blue, grey) or Ultra Copper.  After I open it, screw on the top, and put it away the next time I reach for it has hardened at the opening.  What happens is that I squeeze the tube and in most cases it tears a seam into the tube and it is use it or loose it time.  It seems I waste a lot of product.

I have not had this problem with Curil T, Loctite 518, Hylomar, the 3m weatherstrip adhesive, or anything in a bottle.

There has to be a trick to keep this stuff from hardening.