The oil filler cap on my newly acquired Cherokee just spins and doesn't come off

Do I just bust off the top and spin out the bottom?

I don't want to get plastic in the head

 

Take a flat head screw driver and pry under the top of the cap. It should pop off and then the lower half will still be attatched to the valve cover. No take needle nose pliers or similar and put then down in the grooves on the cap and UT will spin right off.

Nothing will get in the engine I promise, I would in a service shop and we see this all the time.