Store swimming apparels

I haven't swum for a long long time (two years already). Today, I found that the rubber band of my goggles has been either melting or becoming hardened and crispy. The wastband of My TYR nylon trainer (brief-like) has been hardened and somehow melt together as well. My cap is still okay. I also have an unused TYR trainer which seems okay. So I wonder how to store both used and unused swimming apparels? I mostly just put them into a plastic bag, or leave them on the shelve of my bathroom. Is it okay to do that? Thanks!