T. - I guess my question would be, why does it matter if his clothes still smell a little or have some stains?
I worked as a print press operator (ink!!) for 5 years, and I had my "work clothes". They had ink stains, smelled like solvent, and there was nothing I could do about it. So, they remained work clothes, nothing else.
My husband details cars for a living. He always has grease, dirt and grime on his clothes, and he smells like degreaser. I wash his clothes normally. What comes out, comes out, what doesn't doesn't. His clothes are clean, just not stain free! And, when he gets back to work, they are going to get stained again.
I would just take his clothes that he normally wears to work, and make those his permanent work clothes, stains and all.
L.