May I delete cache and application support for Xcode? I'm using App cleaner
Cache: Sure. Haven't noticed anything bad. (You can do this yourself, as well – just trash everything in ~/Library/Caches.)
Application Support: Do not do this without knowing what's in there! Apps often use this to store configuration – for example:


Xcode puts color themes and key bindings there.
The Dock puts your spaces configuration there.
GIMP uses it to hold all sorts of things like gradients and palette images.
Steam uses it to store your entire game library. (If it's taking up way too much space, try uninstalling some games.) Not sure if progress is there too, but it seems likely.



Deleting Application Support won't break the app (it'll just create it again the next time it starts), but you might lose configuration and other data, like key bindings for Xcode. You also might want to make sure the app is closed before you take its folders out from under it. (: