As a blue collar worker myself, we are struggling to find decent help, especially in entry-level positions. There's a lot of money to be made in the trades, and a lot of your education is hands-on. But yeah, summer, or OP could pick up some Saturdays sweeping the floor at somebody's shop. Couldn't hurt. Heck, if it's a field they're interested in, why not get their foot into the door at a shop, so they have an "in" when they're ready to start their career path. You'd be surprised how much people admire "oh yeah, I helped at so-and-so's shop on the weekends in high school!"

It's automatically assumed you learned a thing or two in your time there, which they most likely would. Some of the best shops I've worked at had an apprentice organize all the materials from orders on a Saturday. You go in on Monday, and it's refreshing as hell to see all your supplies laid out, and tagged by job name. Just handling materials, and learning their names is a huge step in learning a trade.

Rambling, sorry