I start by scraping with a gasket scraper than use a wire brush on a drill. I finish by rinsing with carb cleaner and a rag. Too rough an abrasive can/will dig into the aluminum.
If you look at the surface of your aluminum head after you scotch brite it you`ll notice the fine little scratches it leaves on the surface. I did my intake that way and almost ruined it.
the gasket came off intact but there is still very little parts of it I cant get off with a scraper and cleaner. You can feel that the surface is uneven by running your finger around it.
a scotch brite pad works fine on cast iron, not on aluminum for the reason stated above. what i like to use is mr gasket gasket remover. it sprays on and after a minute or two you scrape it off. be very careful though as it is caustic to skin and non metals. it wont hurt the aluminum though.
A sharp razor blade scraper is what I have always used on any gasket removal project. If you have a razor blade gasket scraper that isn't doing a good job try installing a new single-edge razor blade in it and see if your results change. Razor blades get dull fast when scraping metal surfaces with gaskets on them. Remember, the new razor blade will slice you deep if you slip while installing it in the scraper. Leave the shield on the end of the blade until it is installed in the scraper. Wrap the old blade in the shield that come off of the new blade. Wrap it heavily in electrical tape to keep it in place and carefully discard it in your trash.
If you use a razor blade make damn sure its a new one...razor blades tend to dull out and get nicks quickly when dealing with metals of any sort...and nicks can scratch aluminum easy....my advice is keep the blade as close to horizontal as possible and stay away from the edges for as long as you can.....if half the blade goes off the edge of the metal while the other half stays on, it tends to nick for some reason....I have succesfully cleaned thinks like intake manifolds and throttle bodies with razor blades....but I would think twice before trying it with a cylinder head
If it is the original engine I would take it to an engine shop to level the deck. You will get such nice surface you won't get after a week of polishing with hand tools.