Daughter discovered how to take off her clothes. Now thats all she does!! How to make her stop doing this!?

My daughter is one and half and she knows how to take off all her clothes now and fast! Ill turn my back at the store for just a few seconds and she will have her shirt taken off in the cart! Anytime she is out of my sight for more than 30 seconds she comes back NAKED! She wakes up completely naked, and then cries when i put her pj's back on. Like right now, she is getting so mad because i pinned her shirt to her pants so she cant keep taking her clothes off! sad, i know... any way to stop this?!