First pic is a ball rail showing it won't fit in.
Second is the largest item I have had good results with.
Third is 3 pop rings to give you an idea of size and depth.
If you need any more information just ask. I was going to try and get one of the kids or the cat in it for comedy value but they are all asleep.
Should also add that the 3 pop rings were black with either soot or flood crud and as you see them is after 30 mins with Autosol and corncob.
Dried rubber and rust needs a little more attention.