I would be tempted to leave it as is for a bit. Next time you use it, get it nice and hot and scrape off as much of the goo as you can with carefully use of a putty knife.  Then maybe while it’s really hot, pour some water on it as if you were cleaning a griddle and see what happens. 
If that’s not successful, then move on to more aggressive options.
Gerry
	
		
			
		
		
	
				
			If that’s not successful, then move on to more aggressive options.
Gerry