There might shoes that customer tried on in the store and walked around. You can easily clean most shoes with a Clorox Brand wipe. MUST BE CLOROX BRAND (Wipes are cheap on Amazon). Other brands leave soap residue or damage!! If you do not have Clorox brand wipes, use a clean damp cloth, but a clean damp cloth often doesn't work as well as a Clorox wipe.. DO NOT EVER USE A COLORED DISH SOAP!!! Colored soaps can DYE the material!!
It's possible there could be dust or dirt on a pair or two or some other kind of issue simply from being in JC Penny stores.