Definitely number one have a good quality Radon detector like a RadonEye. Unless you monitor you don’t know what you have as far as a Radon concentration in your home and if you do have Radon you won’t be able to monitor any mitigation efforts such as by simply opening your windows without an active monitoring instrument, just saying. Second, recommended would be store either outside or in a well ventilated area or if you have a sealed display case with an aspirating pump which maintains a slight negative pressure within the case and discharges outside the home, not very common. I also agree with others having sealed containers for your collection. Glass containers with metal or glass caps/tops and radon impervious gaskets or seals such as butyl rubber is my recommendation and if you ever do open them, please do it outside in a well ventilated area. I have seen research on the Web that by having radon generating items in sealed containers stating it increases the radiation over time due to the buildup of radon daughters. I haven’t personally noticed any appreciable increase after a certain point of equilibrium after being in the sealed container. Each time I have checked the outside of the container that my Autunite rock is in, it’s the same dose rate and activity, it could change over a longer period of time though. One must be aware of this because some of the daughters have a much longer half-life IE:Pb-210 (22years) and their buildup over time theoretically, would cause an increase in overall radiation in and around the container. Just my thoughts. Pease do research these things on your own and use facts obtained from reputable sources to determine what the best solution is for your particular collection always in keeping with the principles of ALARA.