How many engineers does it take to change a light bulb?

640 pix width.

Size isn't everything

Try a little Never-seize or even vasoline on the threads. A simple strap wrench would also be a little cleaner than a chain or even a damp cloth. That's regarding the lights. You're on your own with the pic size.

Had to read that sentence twice. At first, I thought you made a very funny remark about getting pictures to fit into threads.

Might work there as well.

1) RU sure these are twist on, not clips? Be sure before forcing.
2) SEARS has a nice little strap wrench set with rubber straps & plastic handles.
3) heat it with a hair drier
4) use a damp cloth or one of those rubber jar opener things that are in everyone's kitchen.
5) put a small rubber block against it and tap around until unfrozen
6) put in a drop of penitrating oil and let it work for a day.
7) Ask any lady whose had trouble opening a jar. They come up with some ingenius solutions.

Tap them several times with a rubber hammer. Give it just enough force that you won't damage them. Sometimes tapping them loosens up the corrosion in the threads.

Heat

Mouse Milk squirted in through a machinist's hypodermic syringe might work nicely without making a mess.

But before that, I'd try differential heating as per NYCAP's suggestion. Aircon to 50 F for 6 hours, to cold soak it. Hair dryer or heat gun for a minute to try to heat the outer part without heating the inner part, for differential expansion. Depending on how they are put together, the reverse might be needed (ie: if the removable part screws "inside" the fixed part, you'd need to heat it for a while, then use something like a compressed air gun to cool the removable part).

Dan

How many engineers to change a light bulb..........Maybe none if light bulb manufacturers would make bulbs with multiple elements. Using micro electronics to switch from the failed element to a unused one in the same bulb. The question is how many elements can fit into a bulb, 3 or 5 or more,look how many transistors fit on a cpu.

When you can't find the right tool it's time to make one. However I think the jar opener should work if you can get enough grab. If not, this should work without maring. The handle is 6"

Why not just replace the fixtures with new ones. Chances are it's voltage spikes that are killing the bulbs, LED's burn very cool so water doesn't usually hurt them too often. I've seen some with the entire light assembly full of water and they continued to work. I would honestly go around and unscrew every single fixture cover one by one and coat it with a light coat of anti-seize or superlube, both will help with the water, and they also won't stick

If water is truely the reason they are burning out like CaptJ suggested a dielectric coating over the electronics may be a cure. That can be anyting from a paint on liquid electrical tape (Look for the opaque stuff not the black) or spray on dielectric products,CRC makes some good ones.

A solution from the manufactuer could be to put the entire disk in acrylic,there is enough heat disapation for the electronics while keeping them water tight. Done right the acrylic could act/replace the lens so you only have a single disk ,like a hockey puck to replace. You still will have either spade terminals or 2 wires sticking out,where corission can cause problems. Heat shrink works well.

I love the small cordless butane powered tool Weller makes called portasol P1K. It has a solder tip,hot knife tip,open flame torch tip and a tip that blows hot air with no open flame especially designed for shrinking shrink wrap tubing.It's only 6" long and the diameter of a fat sharpie marker.

Water and electrons never mix, and it's a constant battle to keep the upper hand.

A high end solution would be to use fiber optic lighting with the light source in a dry place........one advantage is you can have a changing color light source for mood effect.

I also realised I did answer the orginal question on how to remove the covers.
If you can't get enough grip from those craftsmen whenches, I make a quick tool by cutting a piece of leather from a old belt to the circumference of the benzel(one side rawhide is best). Then take 2 or 3 smaller regular stainless hose clamps (as opposed to one large one) and make a loop screwing them togeather & clamp down tightly on the leather. The 2 or 3 screw heads will give you a surface to grip or tap with a small non marring hammer. Everyone usually has those SS clamps around.

Good luck.

Yeah those fixtures are pretty sweet right? Make sure you seal up the holes for the wires really good on the big fixtures. A chamois works pretty good as a gripper, but that was before 2 transatlantics! Good luck getting the footlight colors to match, even the manu. gets that wrong. at least those lights only have to turn a half turn to pop off. I used silicone grease to put them all back together.