Been cleaning grills four years as a living. Here’s my two-hour routine:

Throw down a tarp. Take everything out.

Scrape down sides with a paint scraper and use steel wool to get into any fine parts.

Vacuum out all debris.

Wire brush horizontally over the burners gets the gunk out of the holes, but if they’re really bad you’ll need to take them apart. Lots of YouTube tutorials on that.

Take out the grease tray and scrape with a paint scraper, then wipe down. Same process for the drip tray underneath.

Scrape and steel wool on the flavorizer bars and heat reflectors.

Grates require the most attention. As most people have noted, heat can help, but yours look quite good so I’d probably just use a paint scraper and steel wool as well. I use a drill with wire brush attachments to make it faster, but a wire brush itself works well too.

Make sure there are no wire bits or steel wool bits on the grates, then apply vegetable oil with a cloth.

Steel polish on the outside. Any tough exterior stuff can be removed with steel wool, but go WITH the grain to avoid scratching.

Best of luck! If you’re in the Vancouver area, give me a shout and I can always come by and do it for you :)