As stated, soda is not good for rust removal. We have used walnut shells, plastic media, aluminum oxide, glass, soda, and I guess just about everything that will pass through a hose. All this was done because of the risk factor with sand and all were expensive. Now we do wet blasting which is sand with water injection. Way cheaper than any of the others plus almost zero warp due to the cooling water. It is VERY messy with at least a 2 hour cleanup time. Still use soda where paint removal is near glass or bright work on an otherwise finished car/truck. Also use water injection with soda to keep the dust down but it is easy to clean up with just water.
