We are going to continue laundering our own. We had very bad luck with a laundering service. Our smocks were coming back smelling worse than when we sent them. There was always unexplained stains on them when they were returned. We have been laundering our own for about a year now and it seems to be working out well. That is one reason I try not to order from laundering companies. If I do they will not leave me alone about their services.
I understand and I have totally been there. What's up with the unexplained stains? I get the whole blue ink thing where people leave their ink pens in their pants, but I've seen and smelled some really gross stuff coming back supposedly clean. I did some ATP swabbing before of supposedly clean items, and the results were interesting.
However, for maintenance, I would have suggested the laundering service mostly because maintenance guys work hard in some really dirty environments.
From a safety perspective, not sure if you could do this, but maybe find disposable lab coats/aprons with the snaps. I'd be curious to see a sample of what your crew currently uses. Do you have a link to a site where the smock/shirts are bought?