Greetings,
I have two 12x20 Korona film holders that I have been using now for about 20 years.
The dark slides are metal and are now sticking as I slide them in and out.

I am wondering if anyone has any suggestions on which product to use to make them glide smoother.

I was thinking car wax, furniture wax, or maybe Pledge spray.

I keep the film holders as clean as I can, I am a stickler about clean film holders.

Any Suggestions?

Thanks

Gary