Been using Lucas for a while, after it sits it turns dark brown and thickens up a bit.  Never seen any other oil do this without use.

Are you using the extreme duty or the red regular Lucas oil?

Extreme

That is strange, I have 2 bottles that are over a year old that still look green and feel like the same consistency.

In bottle is fine, after being on the gun for a while it seems to turn a dark brown and looks like preservative.

Green? Every bottle I've ever seen is light blue.

I use the red stuff often. I also use the blue grease where grease is needed in some applications. Yes, it does lose its "clean" color after a while. Never had a problem with either the oil or grease but tend to agree that it is likely overpriced due to labeling as a gun oil. Would probably be better served by a tube of marine grease and ledtover syn oil change remnants for less money.

ETA: when my current stash is gone I'm going to use Mobil 1 remnants and a tube of marine grease for probably the rest of my life.

I know this is an old thread but I have not had any issues with my Lucas Gun Oil. That and the grease are both good to go in my experience. However I am switching over to ALG Go Juice just to change things up.