Making an open charcoal grill

I have been wanting to make an open charcoal grill for a while. Saw one at a high school football game- a backyard pro 30" open grill for making hamburgers, brats, chicken etc. The problem is that this one costs $300 dollars. I figured I would make one. I was about to get one fabricated, when I saw a HK 150 parts washer for sale on craigslist. This looks perfect, I am going to pick it up tonight. it is a steel constructed wash basin- 30 inches in length- 16 inches wide and the tank is 8 inches deep. It was used to wash oil off metal parts, I would assume, never used one.

Since I am not going to use this to smoke or have a cover over it, I just want it for direct grill cooking.

any suggestions on how to clean it and get it ready to grill on? the manufacturer website says it is 16 gauge steel constructed.