Sticky Safe? I have a safe lined in the closet at home for convenience....

I have a safe lined in the closet at home for convenience. After 10+ years, it is very tricky to turn the combinations and harder to open or close because it is sticky. Is it safe to use WD-40 to loosen it up or is at hand a special way to move the dial? Any suggestions are welcome.
Can you grease a (hand turned) can introduction?
Answers:    I would mull over oil would get gummy over time and to be exact why they use graphite for lubing locks.

I would start by getting some 90% isopropyl alcohol (or close to that for less water contained by it than 70%) and try cleaning under the knob.

I would think you can't catch in to the lock mechanism, can you? Maybe from the inside near it open? Don't know.

Good Luck.
Whats the max wattage on a lighting ring?...
Minerial Spirits or WD-40 or 3 in-one oil.