Well he did say "depending on the level of rust"...
I usually start at 1000 and move to lower grits quickly. When I hit the lowest grit that does the job effectively (usually 400, sometimes 220, every now and then 80) I clean the blade with that grit and move upwards by grit size to 2500. Then I hand rub with polishing compounds up through CrOx and finish with Mothers.