I just reopened a can of this that I hadn't used much (because I still had an old can of Superslick grease that I hadn't finished) and found that it had turned a very sticky consistency, almost like glue.
I tried applying it to my main tuning slide, and it seemed to _increase_ friction instead of decreasing it. I added a few drops of Hetman #5 slide gel on top of it and that seemed to have made it run better.
Someone else's review mentioned stirring the contents of the can after opening it new, so maybe that's needed if it's been sitting a while too. I haven't tried that yet, but will do the next time I need to apply grease.