I have a WWII USN MK IV Gas mask that I am afraid is unsealed, how exactly do I seal it?

[15cpaolini]

I was going through the garage with my father, and we found his father's Mk IV gas mask. I am pretty sure it is unsealed, and I obviously don't want to be breathing in the asbestos and the 65 years worth of dust. I already know that I need to mix wood glue with water, but I don't know how to pour it in without it clogging the speaking device. How exactly would I seal it, and what proportions of glue to water do I need? (The picture isn't of the one I have, but it is in similar condition, and so you can see it just in case you don't know what it looks like.)

[15cpaolini]

Figured it out! On the inside of the mask, right under the eyepieces, there are two rubber flaps, one under each eyepiece. If you lift the flaps, you can pour the solution directly into the tubes and seal it off.