Just FYI since many of us use them. I was unaware of some of the cautions and suggestions:

Nice information.  I will have to come back this thread if I ever use the grill grates I bought about 10 years ago and their griddle plate too.

The instructions also say to season by rubbing with a cut onion as it is warming up to start seasoning. Follow with a grill spray the first time, and then just the onion will do. 

Did the onion thing. Need to wait until grates are hot enough to bleed the onion. Worked fine for me. Since it was the first time, I also sprayed with canola.  Just went thru the shutoff at 220 and it was also perfect.  I feel strange not cleaning grates up until getting ready for next cook. We shall see.