The trouble with dyes is then you have a clean up job in addition to fixing the leak.
I find it helpful to use strategically placed bits of paper towel or tissue. Taped in place, if movement is an issue. They'll deform when they absorb water, making for an obvious marker. Then use the remaining dry part to swab up the rest. Brown paper towel also works. But stuff like colored construction paper should be avoided as most aren't colorfast, leading back to the original clean up problem.
-- Bill Kearney
2005 Eastbay 47 FB - Solstice