Can I turn in old uniforms any where?

I would give them to a soldier in my unit they would fit.

I just donated a bunch of ACUs to the JROTC at the local high school. They wear them during their competitions and stuff.
There used to be a box at CIF to dump stuff like that, they got rid of them because CIF got tired of accounting for it.

If no one in your unit or the barracks can use them, CIF usually has an old uniform deposit box.