I have 6 outside lights on my back deck. I had these installed about 8 yrs ago when I also had a hot tub installed. The hot tub was sold around 5 yrs ago so I only use these lights very sparingly after the hotub remove. I went to change 2 bulbs that are out. They was nasty/crudy looking around the threads when I went to unscrew them. I did notice I need to clean the glass on the fixtures, as I have green algae building up on the inside bottom of the glass near the lights. This is first time in 8 yrs I have had to change them. Is there a way to lubricate the threads without disturbing the electricity?

If you look at the pic below the fixture has faded alot. I plan on restoring them over the next month. Shouldnt take to much spray paint. Hopefully all the glass can be newspapered up easily.