Yeah, ya got yer roofing nails and yer foundation nails. Don’t mix em up.
You can float them off. Or at least you used to be able to do so. We used to do this all the time when bored in restaurants. Some of the candy coating comes off the m&m itself, which ends up looking a little battered, IIRC correctly, but if I’m reading the OP right, you’re more interested in the intact m than the left-behind chocolate, correct?
Disclaimer: it’s a looooong time since I tried this. Is there a point to this exercise, by the way?
I’ve got to be more careful on this website when I’m drinking coffee. Almost just cost me a new monitor. 
Just get some Smarties.
You couldn’t use those with either the left handed hammer or the hammer with the head at the wrong end?
Those are supposed to go to the Southern Hemisphere.
I bought a bag that had mixed M’s, W’s, Sigma’s and 3’s. I’m selling it on ebay. Any bidders?
The first thing I would try is gently dabbing or rubbing the M.with a trimmed down Q-tip moistened with water.
Are you DLR?
I’m a little confused. Are you after a collection of m-less candies, or candy-less Ms? If the latter, just eat around the m.
Not quite as compelling as the BIL’s diary in his wife’s underwear drawer, but I really want to know why he wants to remove the lettering.
But he’s only a grunt!
Do OP and threadnicks imply generally 1m or “m” if you prefer…or the whole set?
I just love the threadspotting title for this!
Laser?
They sell a rotating emery board thingie at Dollar Tree. Maybe you can gently sand it off.
Dremel tool.
With a Dremel, everything is compatible.
My husband just sat down beside me with a bowl of peanut m&ms.
Well, with an opportunity like that, how could I resist?
The m&m itself, I must admit, did end up rather more battered than I recall. On subsequent consumption by Mr Aspy it was rated “disappointing”
Further experiments will have to await the opening of new m&m packets. Possibly “crispy coating” might fare better?
Say, I like this idea. I wonder whether they’re Unicode-compliant? Then you could get ĉ or ж or even 東 printed on them.
Can I just say that **Aspidistra **rocks? That’s awesome.