I cleaned mine of all the crud hanging off them, fins and tubes and gave them a respray, being close to the coast I thought it a good idea as any bare metal here soon rusts, .... Recent trials show it works better than ever now, 11 years of crap all gone.. I used a 30cal brass brush did a great job on the fins.
I also improved the insulation of the cabinet and ran a thin bead of silastic across the floor so when I pushed the fridge back into place (silastic dry) it made a good dust seal, only place I got a bit of dust was from under the fridge.