I applied liberally to keep the surface wet and allow the solvent to work. I used terry cloth and elbow grease and patience. Resist the urge to use a Scotch pad, it will scuff the gelcoat.
Also, this solvent will not damage most plastics (test it first).
BTW, not available in some states. I bought mine at an autobody supply store in Virginia.
Ok, my pics uploaded in reverse order, but you get the idea.