I only have 1 MAC 15 pan palette, 1 MAC 4 pan palette & 1 Stila 4 pan palette filled.. The rest of my eyeshadows haven't been touched YET! Out of the 24 eyeshadows i depotted, i only ever chipped one. The method i use for the MAC shadows is
1. Blasting a hairdryer on the eyeshadow for 1 minutes,
2. Then i stick a knife down the side & under the eyeshadow & pop it out.
i dont go for all of that baking, freezing, or toaster oven-ing nonsense. i hold my shadows on a metal spatula over a candle, and i pry the pan out with a tiny eye glasses screwdriver. i have a larger screwdriver that i heat up and melt into the edge of the plastic until it meets the pan. when the glue is heated sufficiently, i pry it right out of the pre melted spot with the tiny screwdriver. i only lose a shadow if im not patient enough to heat it until the glue gives extremely easily.
for old stlye urban decay packaging, i heat the screwdriever over and over until i can get all the way under the pan and pop it out.
for the new style UD packaging, mac packaging, and all other e/s with a seperate piece that holds the e/s in a larger pot, i pop out the smaller piece from the pot and heat it on the spatula.
for milani shadows, i treat them as though they were the popped out plastic portion of a mac shadow. ive never had any luck with just heating and pushing through that tiny hole thats already in the plastic.
jane shadows come right out with a tiny gentle pry, bless them. i wish also shadows were so weakly held in the pan.
I've never had a MAC eyeshadow... or their Palettes - so I've never depotted anything in my life besides some pansies! LOL I just use singles or duo's or the ones that come in a kit- I leave at home and just use them in the mornings when I'm getting ready.