Here is an interesting experiment with soluble 3d print support material. Support material used is HIPS (High Impact Polystyrene) in combination to support ABS. HIPS is soluble in Limonene (4-isopropenyl-1-methylcyclohexene). The results look pretty good.
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Here are how to videos and experiments in dissolving HIP in Limonene-D and turpentine: