It might help to put it in a suborbital trajectory, so it would basically go up, squirt, expand to a huge size, and drop back down, being hit by the intended object as it falls. You'd need a lot of foam to knock significant delta-v off the junk, and it would be catastrophically smashed by the thing impacting, but most of it would drop straight back down, and the bits blasted into orbit would be small and light enough to deorbit themselves.