Or you could use the opportunity as greed. Make them agree to pay for a pro cleaning after they use it and agree to pay for a replacement in case of damage.

(Not just because you want it cleaned, though it sounds on the surface fair, but do you really know what they might try to do in your kilt? Do you really want to think of their rears in your kilt if they think it funny to go 'regimental' which you know you would want that cleaned afterwards...)

I do agree with an earlier post, SWK thrifty or maybe even a sportkilt would be a better option, but anyways...