Cleaning a commercial-grade grill surface
If you have dinged or scratched grill that is a problem.

I am used to used to starting with something like this: a grill stone / block / brick.
(Skip the paint scrapper - especially if it is scratching the grill.)
  

If you are using something like this:

Those are also use used but I like a brick.  

Then a green scratch pad on grease.
Then a green scratch pad with water.   

Then just some very very light oil.

This is how a pro does it.  clean a grill like a boss

If you shut it down dirty and fire it up to clean it is twice the work.  It should get cleaned as it is being shut down.  It kind of like lets the stains set.