Now it's time to get rid of all the uncured resin. I suggest submerging the PCB in a container with isopropyl alcohol. That will help loosen up the unexposed resins and any excess globs. You'll want to agitate the PCB by shaking it back and forth in the container.
Rub, Wash and Rinse
Then, use a paper towel to scrub away any remaining resin. The copper pads should be exposed, along with any extra artwork. If not, the resin may have been overexposed (too much time under the UV light).
If your PCB features any through hole components or mounting holes, you'll want to use a tool to poke out any resin that may be clogging the holes. A needle, fine tipped tweezers or similar tool can be used.
Once all of the under exposed resin has been removed and PCB cleaned, it's time to fully cure the resin. Using the UV light, expose the PCB again, this time for about a minute. This will ensure all of the resin is hardened and fully cured.