I can't seem to find an easy way to do it. I've googled it too and it seems I am not the only one. In fact, the most helpful response was to use "brute force"!

I was wondering if any bees had any secret tricks to removing the tray for easier cleaning?

ETA: oh and out of curiosity for you those of you bought the cushion to go with it (I did, it was $5, so i thought "why not?!") - do you actually use it? It was a waste of $5 IMO. I used it once, and had to toss it in the laundry of course, so now I never want to use it because I don't want to create more laundry and L seems fine without it, so I've stopped pretending I am going to use it at all.