So you wore a smock and were super careful, but once you got home you noticed a little smudge of paint on your shirt. Once the acrylics are dry they are waterproof, so water is not gonna do it.
Rubbing Alcohol is the best way to clean up dried acrylic paint, but it tends to evaporate pretty fast. Another great option is a alcohol based gel hand sanitizer, one that doesn't contain moisturizers. Slather it on and let it sit for a few minutes. A little scrubbing with a small brush and a rinse with water typically will take care of most stains. Repeat the steps if needed. If that fails, there is good news. You now have a new shirt to wear when you come back!