A better way? to keep RTV usable.

MOPAROFFICIAL said
From experience or mine at least it seems the cap never gets put on right because the threads get filled with Gunk which dries up pretty fast so mainly it's putting the cap on straight and tight.. and the rest of the thing curing up inside is due to the classic bending and folding like a toothpaste tube imo... so if we can avoid doing that , chances are a tube of rtv will last its contents till actually used up.
Jmo

Just the other day I came across an otherwise brand new tube that had a small amount used ONCE. The cap was put on perfectly. I simply do not understand why the cap does not seal, if sealing is the problem. Got the cap off and had to punch and work an awl deep inside before I hit "wet" RTV and opened a channel to get it out.