First make sure what your counters are made of.
With my first 'used' MH, I bought a real good car wax. McQuires or Mothers with a low rubbing compound to them and I hand waxed the counter tops and they came out real nice.
I since wax the counters on all my new MH's when I get them. I use plain wax not one with a rubbing compound in them for the new counter tops. IMHO A proactive layer of wax helps to keep any stains from ever getting a chance to permeate the counter top. If I keep the MH I will do it at least once a year.