Did you use latex paint? Goof Off will remove dried latex paint, but I'd test it first to make sure it doesn't stain or remove color from your deck.
I've read where others have used Krud Kutter with success.

Don't do any more aggressive scrubbing..........

Thanks for that suggestion....I'll give it a try.

try these steps for either vinyl siding or decking (as I did)

*latex paint -
when paint is wet: start with 100% rubbing alcohol and dilute with tap water at max 50/50 on a white cotton rag and wipe surface

when paint is dry: use 100% acetone (e.g., nail polish remover) and dilute with tap water at max 50/50, with same type rag vigorously wipe

then - since paint will have been spread around (looking like a stain) - use Goo Gone (what I had) and finish the rest until clean, should be now nearly spotless

*oil-based paint -
for wet or dry oil-based paint, start with 100% acetone (e.g., nail polish remover) and dilute with tap water at max 50/50 on a white cotton rag, vigorously wipe surface

if stain from paint is still apparent, use Goo Gone and finish the rest until clean, nearly spotless

I tried a lot of different solutions, literally, except for those that research had informed would be ineffective for what I was doing or would damage the surface (powerwashing, abrasive scrubbing with fine steel / plastic type scrubbers)

This post was edited by craig1721 on Sat, Oct 18, 14 at 16:08