Spray em w/ white paint and let it get worn away, so the colors show through in spots, this was a simple mod that my neighbor used to do, trolled on wire line deep it earned him quite a few 50#+ fish and a couple 60's back in the hey day.
Flap, I've seen a couple all black goo goo's here and there, but not many. I think they were all the 6" size though. Last one I saw I got on eBay as a gift for a friend that collects them.
"Out there in the surf is where it's at, that's where the line gets drawn in the sand between those who talk fishing and those who live it."
- a wise man.