I don’t think you’ll really need to clean the grids Matt. The photos in you post show grids that look they pretty clean already. Unless they are sticky, I think if you just heat them up and brush them liberally with some Crisco and then let them continue to heat this way with the Crisco any bacteria will be burned off and killed. The coating of Crisco will season the grids.
Then bake a first “throw away batch” on both sides. After this you should be good to go for the duration. Every time after this you want to make some waffles just brush the grids with some shortening after the waffle iron has reached ready temp for waffles for the first batch. The waffle iron should stay non stick this way. Over time and continued use the grids will get a darker coating that is a good non stick surface building up, this is what you want to happen.
What ever you do, don’t use a non stick cooking spray like Pam! This will leave a sticky, gummy coating. Crisco or another shortening will not get sticky. After each use just wipe the any excess shortening off with a clean, dry paper towel. I would avoid oil and use a solid shortening, oil can have a tendency to get gummy or sticky on waffle irons when stored between use.
I used to have an old Toastmaster round waffle iron that I only needed to grease for the first batch of waffles every time I used it. The waffles never stuck and it made great waffles. I bought it for $3.00 at the Salvation Army and seasoned it just like I’ve outlined above. I sold it 10 years later for $15.00 at the garage sale we had to get the downpayment for our first home. Otherwise I would have kept it. The coworker I sold it to loved it and when ever I’d run into her she use to tell me it was still working like new.
HTH,
Eddie
[this post was last edited: 9/14/2020-16:18]