Regarding any plastic, capsular container that doesn't allow air to circulate may be fine for coins, but I have doubts as to what long-term contact might be on clay composition or plastic chips.

I stoped using plastic when I lost my first rare plaque in 1998 after storage in plastic since 1990...

...and the most valuable bit of advice I've read on this message board was regarding "plastic-to-plastic contact; plastic bag storage and non-air circulation" to be the best info ever.