Err these are RC's not 1/1 cars, and cryofitting (involves cryogenically freezing and fitting parts together) is generally used to put parts together rather than to split them apart.
Come on, the best solution (by a large amount) is to simply put the slot in them with the dremel, and flathead them out.... it's not that hard is it? how did it go from that to putting ice cubes on the screws?
And for whoever suggested the drill bit designed to remove screws, i've seen it in action and it rarely works. Well I thought it was stupid anyway, had a lot more luck with simply cutting the slot into the screw.
If all else fails, drilling the head off always works for me too.
Trust me I know, because i'm a real expert when it comes to stripping screws, so it's a given i've tried every trick in the book for getting them out.