I didn't sandblast my frame. I just went over it with a wire knotted cup wheel on a highspeed hand grinder, a drill with assorted wire wheels, cup brushes, a hand wire brush for some tight areas and even a chisel that I used by hand to chip out any pitted areas with. Then treated it with a rust inhibiting paint.
Is this the best way, no but sometimes space and equipment and funds don't allow for the best option......
John