So my sim tray was really stuck, and I mean STUCK. When I pushed a paperclip in (quite hard!) it just would not do anything. So I was struggling with many bent and munted paperclips, trying to snag it to the side of the little hole and pull it out. But the tips of my fingers were getting pretty sore.
So I decided to get some pliers with a good grip on something like a nail. I looked around the tool shed for something more sturdy than a paperclip like a thin nail or a very small drill bit. I found a drill bit that was thin enough and tried to use that. I gripped the drill bit with the pliers and pulled. However, it kept snapping off (which was quite helpful because the shorter it was, the more force it could handle!)
I eventually pulled the tray out with about 4mm of drill bit that I'm never going to use again!