You may have seen in my videos that I squirt water onto the hot griddle. The steam it generates cuts right through the food and such so that you can easily scrape it off and into the drip pan.
After the scrape, I get a paper towel mop, squirt more water and wipe it down good (better use gloves). After wiping it down, I let it cool down a bit - still pretty warm. Then I get more paper towels and spread a light coat of lard to protect the surface till next time. You can use canola, peanut, or vegetable oil, but my doctor advised me that the animal fat like lard was better.
I keep my griddle covered with the built in hard cover, too.
BTW, there are numerous videos on this topic on YouTube. Watch some of those for REAL advice.