For heavy oil, either the BigTime or Smashtime. I have the Bigtime and I took it down to about 600 grit because our house has been putting down a flood of oil whereas I could not get a XXcel box finish to turn more than a few boards. This ball started picking up a little past the arrows and was almost rolling out on a condition I couldn't get my other balls to get into a roll! It's strong.
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If it weren't for electricity we'd all be watching television by candlelight.