Can I still cook on my propane grill with rust? I busted out my propane grill which I haven't used in over a year and noticed as I was cleaning it that there was a bit of rust on the grill.  I tried to get it off but it doesn't seem to want to.  Is it safe to grill with some rust on there?
Rust, or iron oxide, is not poisonous, unless consumed in large amounts. Thus it is relatively safe to grill on your barbeque.

What about the people who get cut by rusty nails and get lockjaw? That's not due to the rust, but rather, due to the bacteria on the rust, which is called, Clostridium tetani, which is found in the soil, and presumably, the nails have had come in contact with the soil, and so actually contains some of these deadly bacteria, and so, when a wound is made by the sharp object, the sharp object(nail) will also infect the wound causing tetanus, or lockjaw.

Which is totally irrelevant to your grill, as I assume, it hasn't actually come in contact with the soil has it? 

So, it's safe, relatively