heat gun would be one thing to try
but the plastic may burn or harden up under heat, no way to predict (instead of melt)
plus you may overheat internal parts, like the battery [fire smoke etc]
There are several Nitecore lights like that, the Surefire Sidekick, Fenix E03R, Astrolux K1, etc. I think of those without having even looked for this type of light. Iām not saying those other lights are better. Just that there are other lights in the category. I donāt even understand what is attractive about the form factor, though thatās just me. I prefer lights with swappable batteries unless there is a compelling case for an internal one, which usually means the light is tiny, e.g. Nitecore Tube.
With the heat gun, I think you just have to be careful.
As for rebuilding: Iād want to reprogram the software to customize the UI, make both leds white or else one of them deep red (670nm), and put a raised ring around the pushbutton to prevent accidental activation. Lockout mode is a clumsy workaround imho, for a switch that is too easy to activate accidentally.
Iām not trying to slag on this light, I just find the disproportionate attention it gets to be a bit perplexing.
When I say "inexpensive," I'm talking about approximately $20 or less.
Surefire Sidekick is quite a bit more expensive and does not have a lockout feature.
Astrolux K1 does not have a lockout feature.
Fenix E03R is kinda expensive, and provides less lumens.
Are there any other keychain flashlights that you think might be in the competition, because those three aren't, except maybe the Fenix E03R (if you want less lumens for more money.)
A lockout device only means that the switch is so badly designed that it needs a lockout. So Iād consider the presence of a lockout to be a minus, unless the light is a total failure. The Surefire seems like a nice light to me.
Did you look at the Nitecore Tip and its close relatives?
Here is something cheap, no idea about quality:
https://www.aliexpress.com/item/32803090535.html
I have to say this format of light just doesnāt excite me much. I prefer normal swappable batteries. Also, all of them are too large for a keychain imho. Lumintop Pimi is closer to the right size, or Sofirn SC02 if you can stand a little more size for greater convenience.
I donāt understand the notion of wanting a perfect light to be cheap, either. When you find the perfect light, buy it, pay whatever it costs and stop worrying. Low priced lights are for when you want lots of them.
For me, the perfect keychain light is the Photon Fanatic LPK, which was relatively expensive by BLF standards, and also quite low lumens compared to these rechargeable lights. I like the idea of a Pimi-format light with 20 or so lumens and proportionate runtime. More powerful lights are nice in their own way but I havenāt desired one on my keychain so far.
Most (if not all) keychain flashlights that don't have lockout, need lockout.
Trust me, I've used plenty of keychain flashlights, and all of the ones that I've owned need lockout.
Yes, I owned one of the earlier versions that had lockout.
They are not made well, and it fell apart.
The newer ones don't have lockout, by the way, but since they're not made very well, it doesn't really matter.
You can buy expensive lights if you want to.
No one is stopping you.
Go ahead and waste your money however you want.
But I'll look for high quality inexpensive lights, and of course, I'm not the only one.
Maybe you'll feel more at home at CPF with their love of overpriced flashlights.
This is Budget Light Forum, after all.
Of course, this is BLF. But, if you are still looking after all these years, maybe a different strategy might work better ;). Fwiw I havenāt felt that my money was wasted when Iāve bought nice lights. I canāt afford to buy lots of them, but the ones Iāve had were mostly very satisfying. If youāre into flashlights as a hobby but focusing on lots of cheap lights instead of a few good ones, you might be missing out.
I donāt feel that the D4v2 with the raised switch ring needs a lockout. Itās not a keychain light but it shows that itās possible to make a well-enough-protected pushbutton to not need a lockout. Iād say the same of lots of tail clickies Iāve used, but those lengthen the light enough to not play well with keychains.
Iāve similarly had a LOT of small twisty lights and none of them have needed lockouts, unless their threads were loose enough that Iād call them defective. Do you require a pushbutton?
Iām not surprised to hear about Nitecore being crap. It fits what Iāve heard in general about them. Oh well.
Read my post again about lockout.
I'm talking about keychain flashlights, not all flashlights.
Here in EU, I get this price
Subtotal
US $20.38
Store Coupons
US $1.00
Shipping
US $0.00
Total
US $19.38
Not so good, compared with prices mentioned above. 
Kind regards
@gregor:
Strange.
It's still coming up $15.70 for me.
You think that I should start buying expensive lights when I'm very happy with high quality inexpensive lights?
Whatever you're smoking, I do not want.
Are you telling me that the SC01 is not a keychain flashlight? Or that it needs a lockout? I canāt tell which.
I would call the SC01 a keychain flashlight, it is inexpensive, and I havenāt heard anyone say it needs a lockout:
As for pushbuttons, I havenāt seen anything youāve said about lockouts that is different between keychain and larger lights. Itās just that the keychain lights youāve been using have crappy switches.
Lockout only applies to keychain flashlights that have buttons that can be pressed easily.
If there are no buttons, lockout is irrelevant.
If the button cannot be pressed easily, like with an AAA flashlight with a tail switch, lockout is again irrelevant.
It really seems like you're desperately grasping at straws with every post you have made in this thread so far.
Didnāt you say you are still looking for the perfect one? Iām not looking, I have found mine (the LPK) and Iām happy with it. Iād also say, the perfect one doesnāt need a lockout because it doesnāt activate by accident. The presence of a lockout is to compensate for an imperfection. If youāre still going through lights with lockouts, youāre nowhere near the perfect one yet.
It really seems like you're desperately grasping at straws with every post you have made in this thread so far.
Speak for yourself! 
I bought this light because Mila Kunis said it was a good light ...She didn't say squat about a lock out .
You are from USA, CA.
Iām from EU, Slovenia.
This is very likely the reason for different price. Probably VAT related.
EU members on this forum, can you check what price you get?
Thanks.
What price do you see here...
https://www.aliexpress.com/item/1005003103586011.html
Is it $16.70 before the coupon?
No, itās higher:
Very likely, VAT related.
At AliExpress Iām getting 18,36ā¬ for a black with white/UV leds.
I have some coins, so it drops the price a little bit.
Shipping is free and VAT is included already. It seems to be in promotion, as the price seems to be higher.