One issue with storing soap without any wrapping is the soap loses its scent faster. Otherwise the main requirements are to store soap in a cool, dry, dark place. I'd also give some thought to storing soap in a way that reduces dust and prevents mice from snacking.
Here's an interesting read -- http://soapsmith.blogspot.com/2015/09/soapsmith-dos-experiment.html
Here's an interesting read -- http://soapsmith.blogspot.com/2015/09/soapsmith-dos-experiment.html