On occasion I’ve gone into my iMac’s top library file and found up to a couple of gigabytes of Mail messages duplicated there for Apple-only-knows-why. This time, there was very little, but I stumbled on another memory-hogging cache full of advertising images I’ve never looked at except to note their and trash them. They’re all from online catalogue sites where I’ve gone hunting for particular items and had to wade through pages of these other items to get there. You might want to check on how much space your browser’s wasting with this stuff: To get to the main library, if you haven’t had occasion to do that before, press Go from the Finder’s main menu, hold onto the drop-down menu that appears, and press Option to make the normally-hidden Library destination appear in the list. Open that and all kinds of neat things show up. The cache I cleared out today was at Library/Containers/com.apple.mail/Data/Library/Caches/com.apple.mail/fsCachedData