Lori
The rust might flake off when the grill is heated and may end up in your food. That would not be healthy/good! You're better off trying to replace the grill plate. Maybe try Ebay or craigslist to get one at a lower cost (you might find a cheap grill that has a good plate that fits yours). Good luck!

Nora Bahgat
No it's not safe because it possible that this stuff could end up in your food which isn't a healthy thing. Clean it or buy a new one.

sweetroll
Try and scrub the grill with a brillo as much as you can. The rust won't hurt you but you probably don't need to have your food cooking on rust. You might need some really hot water and soak in a sink. Replacement grids are usually available if the grill isn't too old. Sometimes big box stores like Home Depot or Lowes might have them when BBQ season is on. There might be kind of one size fits all type of replacements too. I had a gas grill only once and prefer charcoal totally. Good luck with your grill.

bout83
if you cant get a new grill, there is an aluminum foil that is made for grilling, cover the plate with it. no grill marks but, but you'll still have the flavor

slyrchell manaig
you can try the foil method just like one of the posters said or you can try look for a replacement if your opting to use that grill for awhile.