[HO455]

I would talk with the vendor or manufacturer before attempting to remove it as some springs come coated with an antisqueek/lubrication coating. If this is not the case with your springs then removing the coating by sand blasting isn't the best idea. The grit will get between the leaves and cause squeeks and the springs will not slide properly against each other causing your springs not to have the same reaction to bumps. The same problem will result if you sandblast each leaf individually as there will no longer be nice smooth surfaces for the leaves to slide against. Over time the leaves will slowly polish themselves but you also take the risk of two (or more) of the leaves not polishing and instead gauling each other.
Properly designed srings will have some form of lubricant (even if it doesn't look like it) between the leafs to prevent noise and premature wear. In the past when I have rebuilt old springs I have disassembled, wire brushed, polished any wear patterns out of the leaves. Before reassembly I coat the mated surfaces with thick graphite grease. (I.E. semi truck fifth wheel plate grease). After reassembly carefully clean the tops bottoms and sides so not to wash the grease from between the leaves with mineral spirits. Then I spray paint them with flexible bumper paint.