My thought (having never done it before) would be to use a microfiber cloth and some sort of 100% liquid solvent. Acetone or Isopropyl alcohol, gas or kerosene, paint thinner/MEK/Xylene/Toluene, in approximate order of strength/health hazard…
whitecitadel that made me chuckle
Thanks for kind words all
But really please don’t say “Miller and team” it is the team despite my newbism that pulled it off and steered the project the right way.
In hours money and energy surely Tom has spend most, so if one want to name please say “Tom and team”
I only can compete with Tom on time spend but that could also mean I need to do things more efficient 
I have a Wuben light with triple XPG3’s and the AR glass causes a tint shift. I’ve tried iso alcohol, acetone, and a Cape Cod polishing cloth. I let the lens soak in acetone for an hour. None of those three things worked.
btw, Rinse the acetone off with water first before using a microfiber cloth. Acetone will melt a microfiber cloth.
My searching how to remove AR coating all make it look like acids can be used.
A lot of the info online about removing the coating assumes the glass is made of sapphire, and won’t necessarily work on regular quartz glass. Hopefully I can get the rest off though, because at the moment it’s kind of a mess.
Oh boy... I'd go by the chemical tips above, in order, just stay away from anything abrasive. Glass has great resistance to many chemicals. I haven't been "blessed" by seeing an AR coating yet on a Q8. Hhmm. I know I have one extra clean glass Q8 lens though, so any time you want it, just say the word.
Wow!! My head is bout to pop from all the swell'n. Thanks for all the kind words above!! Though many contributed, I feel somewhat responsible. Dunno how you do it TK - but deploying firmware like this into production lights is one big, nasty, gut wrenching experience. Always afraid of that big bug that will pop it's head up at any moment.
I've written some high risk code for sure, but kind of feel you got 100's of people behind you in a company, and you didn't do it alone. Some of my software adventures:
- ground radar display system for the FAA, deployed at every major US airport - was that a plane or pacman on that screen? Love the fact blimps go undetected.
- Special OPS mission planning w/loading the mission parameters into the black helicopter's on board nav systems - which hemisphere are we in?
- medical radioisotope dose measuring systems - was that in micro Curies or mega Curies? Ooops!
- rehab isokinetic machine - Velcro strapping the elderly or surgical recovery patient into a machine that can go from 1/4 deg/sec to 500 degs/sec almost instantly - can bury an attachment into a wall or floor if the control loop fails... etc.
I’ve been trying, but so far the only thing with any effect has been physical abrasion. I just soaked it in paint thinner for 2 hours and then scrubbed it with some thinner-soaked cotton pads, and it appears to have done nothing.
It sounds like you’re having a good time? 
I don’t get much of that out here on my space rock. Come to think of it, I don’t think I know what it’s like to not be alone.
Why not abrasive? Just something mild like this specific glass polish…
Received my two lights, second batch. They are awesome, no flaws as well. One quick question, when ramping, before they reach the highest level, they have a quick flicker, is that normal/supposed to happen?
There is a brief flash at both max and minimum to let you know you are at the limit.
You can see it here at 3:40 to 4:25.
If you see a flicker before max brightness, that might be a bizarre defect. Are you sure it’s before and not right at max?
You are correct, that’s what I’m seeing. Thanks!
From the Way Back Machine part of my brain: I believe a good AR job is actually vapor deposited in a vacuum. It could be a chemical deposition process. And I think it is all or most various metals and various other materials in layers. Generally speaking, a solvent should not really bother any of the layers.
An acid bath (and maybe a base bath - in sequence) may be needed.
If you have a suitable laser and real good adjustments, you might get it off without hurting the glass/sapphire.
That was also my intention. But after about a minute of using the default ramping - I love it!
I gotta say this is more flashlight than I thought it would be. More than I need. I didn’t think I’d say that. It is simply a beast.
I bought 2 Q8’s and set one up in mode set and left the other one in ramping. After 5 minutes I changed the other one back to ramping 
French Press has been my go to for several years now. But I’ve never used a Burr Grinder. Any recommendations for a good one to get??
Just got mine today….and I really really wish that I had bought a second! Fantastic job! Thanks for all the hard work everyone involved!!!
Now, I have read the info….but can someone please tell this dummy, in small words, how to configure the modes? I read the sheet a few times, but still can’t seem to make it happen.
Do you mean change the menu settings? Try here:
Good reports!
Nice!
So cool how well received ramping is.
Had to get a new one, the old, traditional model just was too old and made some parts too small,others too big.
I ordered this:
https://www.aliexpress.com/item/Ferris-Wheel-Design-Vintage-Manual-Coffee-Grinder-With-Ceramic-Movement-Retro-Wooden-Coffee-Mill-Coffee-Bean/32787751010.html
I thought it would look nice in out kitchen.
Works like a charm, nice fluffy grounded coffee.
And I can fit my battery powered drill over the top to make grinding faster in those cases I need more then just enough for the French press or stove top espresso maker (yeah sometimes they are being used at the same time, and then i grab the makita to let that do the work )
Wait, a burr grinder and french press are not metal fab tools? They are coffee related things?
Whew, I was wondering why I’ve never heard of these tools before. Lol