If it were me, I would remove all items able to be taken out–you should be able to remove the element, too.
If you have a deep freezer, I would put the racks inside there, and let the plastic REALLY harden. Then take a non-sharp edged tool, like a spatula or pancake turner, and scrap the dickens out of the racks. Get as much off as you can. Then, pour boiling water on them–from the stove.
This may feel like alot of shuffling, but it will save you a ton of cash in the long run…
Is there a ‘puddle’ of plastic on the floor of the oven? Make yourself an ice pack from zip bags–chip away at it, and then use the hot water trick–off and on. It may take a few tries…
As for the element. If it were me, I would play it safe and purchase a new one. They are not that costly and usually just plug in and out. You will feel VERY EMPOWERED. Now. I would STILL PRE-HEAT AND PRE-COOL the oven a few times with the windows open and fans blowing… just to be safe. Your lungs are your ‘center’.
And for the True Issue. Next time, just plug the sink, fill it with soapy water and toss the dishes in. No one will fault you!
Clean Slate Professional Organizing
Western Wa State.