The inside of the replacement J5 V2 Tactical Flashlight doesn’t have quite as much dirt on the LED emitter, but it’s still pretty bad:

The small white dingus at about 10 o’clock seems to be a plastic shred stuck on end to the emitter lens. Here’s a better look, rotated a quarter-turn counterclockwise:

There’s also an alien egg glued to the heatsink beside the LED:

I’m hoping it’s another random plastic blob.
There’s no point in returning this one; it’ll suffice for my purposes. However, given two random samples, I’d say the J5 Tactical Flashlight factory, wherever it may be in China, is really filthy.
I’d hoped that paying a bit more for a “tactical” flashlight, instead of going bottom dollar, would yield a better product. Maybe it did?
I’ll take a look at my bottom dollar flashlight emitter when it resurfaces. I’m pretty sure I’ve taken it out of workshop to change the 18650 cell few weeks ago but it seems to have grown legs or other means of autonomous transport since then :)
I can’t imagine the conditions required to get that much dirt into what should be a simple assembly. If your flashlight came from any ordinary workshop, everything behind the lens should be spotless… as are all my other cheap LED flashlights.
Assembled in not-so-clean room conditions for sure.
Might not be ideal for your application, but I think I’m still seeing purple and yellow lines from a friend’s Cat CT1000 – http://www.catlights.com/product/ct1000-pocket-cob/ – when they say “don’t look into the beam”, believe them. It doesn’t have great battery life, but is small and scary bright. Uses an LED type I’ve never seen before, too.
I’ve put cheap eBay COB LEDs into a few projects around here and like ’em a lot: plenty bright and easily mounted on heatsinks. I never considered a “flashlight”, although it makes a lot more sense than the usual concentrated beam.
Zooming the J5-V2 lens to the big end of the slide lights up the entire end of the living room; something a bit more rectangular for closer work would be better.