Because cartilage does dry out with age, it can't hurt to drink the two quarts of plain water your body needs daily. (Many people -- especially older women -- don't drink enough water.) This will make all of your organs and tissues function as smoothly as possible.
And while it's true that certain oils do have a place in arthritis therapy (fish oil and evening primrose oil, for example, have been shown to reduce pain and joint inflammation in some patients) they don't act as "lubrication." Ask your doctor if they're appropriate for you.