I have a ~10-year-old 16 oz can of Park Polylube 1000 grease, stored in my garage. I've used about 1/2 the can. When I bought it I figured it would be a lifetime supply. For the last couple years I've noticed a small pool of green liquid standing in the can whenever I open it. I've tried mixing it back in but this doesn't really work. I'm not sure the separation is bad, but it probably isn't good.
Just noticed a Lifetime Warranty at Park's website - I may request a warranty replacement for my runny grease.