Where you at?
Northern VA.
I have to constantly run more solution over the parts as they dry up. Are you guys doing this?
That's what I mean about the gel thing being too much trouble. Streaks, drying out, multiple applications... Submersion in liquid is the easier way, dunk the thing, leave it in the hot sun and forget about it for a few hours, and when you come back it'll most likely be looking good. Here's another item I did recently.
Before:

After:

Again, it was done in 8 hours or so on a sunny day in something like 50/50 H2O2 (40vol) and water.
If you really want to have some fun, grab a magnifying glass and focus the sun on a small area. You can watch the plastic lighten.