storage of baseball

I am an avid collector of baseball memorabilia. I mostly collect autographed MLB baseballs. I am trying to find out the best way to store the baseballs that I do not display. I often bye memorabilia as an investment and I am curious what is the best way to keep the baseballs from fading or toning. Currently I keep my baseballs in their original boxes which are in a dark closet. Inside these boxes the baseballs are wrapped in the tissue paper that comes with each MLB baseball. Is this thin piece of tissue paper doing anything? Should I put them in plastic sandwich bags, or do anything else to preserve them for many years? I know Steiner puts their balls in plastic bags. If I do this do I have to worry about any acid breakdown over time. Please help. I plan on keeping these baseballs for many decades, and I would like them to stay in their original condition.
Any tips would be greatly appreciated.