That is one great looking uniform. Glad to see the bonnet in lieu of the glengarry.

But, if it was mine (and it isn't, so just ignore this), I'd take the bonnet and give it a good drenching in the sink. Don't wring it out, just squeeze it a bit and let it dry outside, proably in the shade.

I've done that will all my bonnets (4), and it really adds character and a nice lived in look. (Read Scotty Thompson's relayed advice in So You're Going to Wear. . . It works.