cleaning grundge

[BigZ]

I'm replacing my wooden handrails with SS rails on a 74 Ranger 26. The problem is each footprint of the old wooden pads are several inches long and the attachment of the new rails are much smaller. The old footprint at each attachment point has 30 plus years of dirt, varnish, sealers, etc. smooched into the non-skid. This old footprint looks nasty. I've used Bar Tenders Friend and some bleach products trying to clean it before I put the new rails on but it is not coming clean too fast.
Is there some magic stuff that will clean this up or should I just mount the new rails and let a summer in the sun loosen the this previously hidden crap?

Again, all connections are on non-skid surface..

Thanks

[sailingdog]

Try a Mr. Clean Magic Eraser.