Would cooking oil work to keep snow from sticking to a dish or is it a futile battle? Got a storm going by dropping 8" of wet snow that keeps sticking to the LNBS and two reflectors of my T90 and it's a pain not being able to watch TV.
I would think cooking oil would eventually freeze and get gummy, thereby allowing accumulation of snow/ice on the gummy surface. I tried the "PAM" on the dish thing back when I was subbing to the pizza guys - it never really did anything except make a mess. What you need is some of that stuff that Chevy Chase made and put on the bottom of his sled... that stuff should do the trick
Try windshield washer fluid with "Rain-X". Pour some in a small spray bottle and spray your dish and lnb. We get lots of wet sticky snow here and it works the very best, snow slides off and won't stick. Its cheap around $4.00 a jug, and one jug lasts all winter.
I might try the Rain-x idea. A garbage bag over my T90 probably wouldn't last long with the sun beating on it. I also think it would end up sagging with the weight of the snow on it being a big dish with a not so small second reflector.
From what I've read of rain-x, I wouldn't need much. And don't use it on a windy day because it apparently can cause blindness if it gets into your eyes. Let alone inhale it.
You could also use shrink wrap, I bought some on ebay and wrap my condensor on my HVAC and my fountain in the winter time, it lasts fine in the UV, pretty cheap, it cost me $10 for a roll of it on ebay.