Google aerobic and anaerobic bacteria. The worst thing you want is an oxygen deprived environment. this is what happens with sealer caskets. The good bacteria that use oxygen soon used it all up, the nasty anaerobic bacteria takes over and you get major gases, gooey mess. What you need in a good mausoleum is good air moving ventilation. The casket itself needs to be breathable. This venting should run the length of each floor of a mausoleum and vent up at a high point away from public area. This air drying out is the best you can hope for and will keep you around for years, unless you go for the Egyptian organ removal and get predryed out. With the sealed, zero O2 environment you will within 3-4 weeks start turning into a bloated, gassy, gooey mass. The problem is the big buck gouging of useless services and products that the funeral industry has morphed ino.. Embalming is totally useless except for viewing based a few days and basically puts a nasty chemistry set in the ground with each body. Unless heavily over done as some heads of states and their wife’s, embalming does nothing in the ground. Gouging? Gee, some states require a fully equipped preparation room just like a funeral home at crematoriums when it is not needed nor even used. You shouldn’t need a licensed mortician, but you do. Such is the lobbying power of this industry that is right up there with used car salesmen and dog crap on my sneaker.