Injector seat cleaning 670T

Somebody may have a better way but id plumb a air line into the intake manifold with some way to control flow. Air will come out which ever cylinder the intake valve is open on. Air flowing out will help prevent debris from falling on a piston
Take a round brush on a drill a little larger than the injector hole and clean the hole with air coming out. Rotate the engine until air comes out a different cylinder. Cleann that one and continue the process until you have done them all

Thanks for the replies, all the copper washers are out and I plan on replacing those. Just trying to get an idea on how to clean the crud out of the injector holes without it dropping into cylinders.

I suppose you could drop a short bolt in the hole then scrape around the bore to "clean" it then hold down on bolt while blasting air in there to purge hole. Finally use pen magnet to pull bolt out. Were the rubber dirt seals missing on old injectors?

Thanks everyone, the rubber dust shields were in place, just looking to clean up the flaking rust from bore where injector slides in. Looks like tractor has sat outside for some time as injectors were kind of rusted in place. Top surface of head I was able to get reasonably clean. Plan is to use big shop vac and wire brush to clean up bore and the address any carbon build up on seat where copper washer sets