I recently fired some .38 special loads I had assembled from mixed used cases, a hand cast bullet, Lyman 357446, which I had lubed with alox/beeswax lube. These were assembled in 1967. No attempt at sealing was made. They functioned absolutely perfectly. My daughter, born in that year, was impressed.
I suppose I would use factory ammo if I were going to be doing some serious shooting in a humid environment. Sealing just doesn't seem worth the hassle. Walt