Did you ever try pulling the fridge out just far enough to get behind it with a vacuum brush first? I used to do the full pull out too and it wrecked my floor every time. Now I hit the coil from the front with a soft brush attachment, then follow up with the hose, and it gets way more junk than you'd think. Only thing to watch is the water, go light or you'll soak the insulation and the pan underneath. If the coil is really packed, do a dry pass first so you're not just pushing wet dust around.