I've tried to remove mine now and my hint would be to compress the foam to reach the white plastic base with your nails, and pull them very firmly. Since they aren't soft foam, the force will be actually used to pull the thing off.
After you do it for the first time you will lose the fear of breaking everything apart :)
When I compressed the foam to remove it, I thought I had damaged the tips because they looked very bad. Less then a minute after that, they wer back to their original size and look. No worries there, as long as you don't do that every single day, I guess.