Take off the inlet valves (the black discs on the side of the cheeks) and look at the filter. It should look white with a fine mesh of material over it. If it looks in good shape, you can probably use it with no problems, but please ask a responsible adult before you play with it. The mask is a serious piece of military equipment and has hidden dangers.
The filters were designed to last 24 hours in a contaminated environment but they do degrade over time. The filters will probably offer no protection of any kind now since they are so out of date.
I'm in the process of writing a report on the M50 gasmask and its history. So far I've dug up many patents related to the M50 but I'd like to look into the more detailed aspects of the M50's development history. If you have any references I'd be happy to share what I have
Wow, you are lucky...you don't see these suits too often anymore. They were being phased out when I was on active duty and the POTMC suit's purpose has been filled with various Level A suits (another encapsuilation suit.) These were used for EOD missions so I didn't see them during my career (I was never EOD qualified). I did some googling and came up with some info though:
Hi, I’m in the process of buying a M50 respirator from in the military and was wondering if there is any paperwork I should ask for to prove that it’s not stolen or anything and you seem like someone who would be able to provide the answer I’m looking for.
Thanks in advance!
You will want to keep the recipt of course or at least a photo of it to archive. However, I wouldn't be too concerned. There are hundreds of thousands in the system and many will find their way to the secondary market. Most of the time, a mask is issued and not retrieved by a supply sergeant after the Soldier PCSs or ETSs. These are sold to the local pawn shop or military surplus store. The military itself might sell these at DRMO for servicability reasons or simply because of oversupply in some region. If you are too concerned, Avon will gladly sell you a C50 mask which is the same mask but for the civilian market. However, I don't think anyone will challenge you owning an M50 protective mask.