So far I have been using a soft wire wheel on a 6" bench grinder. When it gets to the frame and other parts I will be using a soda blaster. Using the wheel takes a little time but it seems to work well.
I used to do auto restoration, used up a bunch of wire wheels. There are other things to use, but that is cheapest and less damaging. If you know anyone at a machine shop you can have steel items hot tanked. Walnut shells work well as a blasting agent too. I love to see old forgotten things brought back to life, it is one of the most rewarding things I've done.
Thanx for the info, this is the first project like this I have done. I am going to take it 1 piece at a time.