What do I need in order to deduct uniforms from my taxes?

I buy shirts and ties for my place of work, I wasn’t sure if anyone knew the amount that could be deducted for the entire year and what you needed to prove you bought it all.

I shop at Kohl’s and for some reason they don’t have a customer database and can’t look up my transactions (I find it almost impossible to believe ). I was hoping they would be able to just re-print my old receipts, but they told me they couldn’t.

Am I screwed for trying to get that money back on taxes now? Or is there something else I could do?