May not work on your flies but for the Great Lakes some of us use Fantastic cleaner (the original not the industrial strength one) and spray it on socks etc. Do not spray on floor as it is slippery. Some people find it hard on their skin. Works better for me than DEET.
I spray it at places that I will be cleaning at the end of the day like coolers, top of gunnels etc.
" The only boat without a ding or two, is the one that never gets used!!! "