Bought this from FT just over a year ago, never been out of its anti-static bag,
the crap is actually in, not on the dome, not on the phosphor, you can tell this because it is in focus and the phosphor is not, not much depth of field at that magnification even at f16 :disappointed:
One of 6 and all have crap in the dome, so seconds, looks like I am going to have some domes to soak off 
Cheers David
Where did you get them? Could they be lattice bright leds instead of real crees?
FastTech, I’m pretty sure they are real Cree xp-g2 (of the old type ), they shove out about the right lumins and are white not blue, are there lattice bright xp-g2 ?
Cheers David
Try cleaning it with some isopropanol
This.
I’ve found the little disposable alcohol lens wipes work very well for cleaning crud off domes. Unless the crud is burnt in to the dome this should easily get it out. I’ve only had stuff become burnt in to a dome when the soldering iron tip slips and hits the dome.
If that doesn’t work… well if you have old-style XPG2s, they should be good for dedoming.
I always take a tiny piece of paper towel. wet it and stick it on my emitters before soldering anywhere near the emitter . I use a lot of flux and think it can’t hurt to cover up .
I’m guessing nobody in china uses protection
I usually take the cap from a ballpoint pen, cut it off just enough to fit over the emitter, and then I always solder the leads with the dome protected. Not going to help the OP though 
Yup.It looks like flux or solder spatter. Alcohol wipes, sometimes a soft toothbrush and alchahol are in order.
Thanks for all the tips 
Not my soldering they were purchased on the star, now I know why they were cheaper on the star than loose, anyway I have a big head Courui that has spotted them and is demanding one dedomed, pencil beam anyone 
Now I just need to wait for it to warm up a bit, metal garage and cold wet winds are not good for the rheumatism/arthritis and SHMBO will not let MEK inside no matter what 
Cheers David
Get that bad-boy into some warm paint thinners, & you will have a perfect de-dome
Definitely good old XP-G2… Rare beast this days… Congratulations.
Oh forgot to say: Isopropyl alcohol bath and wipe with some soft cloth… Repeat if needed and blow with compressed air at the end.