I bought an old school 1970’s Philadelphia Sixers t-shirt the other day. I hate that its so clean and new looking though. Any thoughts on how I can artificially “age” the shirt? I don’t want stain or ruin it, just fade and wear out the material. Will washing it with sand or rocks work? Will that break my washing machine? How about leaving it out in the sun for a day or a light mist of bleach?
Put it in the washing machine with a couple of largish rocks.
Bleach might not fade it evenly.
Rocks!?!?! Kids, do not try this at home! 
Give this a try: go buy you some of those really coarse scrubbing pads (3M makes some that are green, I think). Put two or three of them inside a lingerie bag or pillowcase with the shirt. Wash with a load of towels (to provide something for it all to rub up against). Repeat until desired level of wear is achieved.
KneadToKnow, that sounds like a good plan, and i never would have thought of it. thanks. 
Add a cup of bleach to the washing machine, and only fill the machine half way with water. Putting it out in the sun won’t do anything.
Let me wear it for a day or two.
Put it in the sun. I have mine in the sun & boy is it looking old already.