Treat Clothing With Permethrin
The CDC recommends using permethrin (both a repellent and insecticide) products to treat your clothing. There are products designed specifically for treating clothing, and they are considered safe by mainstream standards. Of course, this requires that you follow the product’s directions exactly as listed.
The benefit of permethrin treatments, aside from not applying it directly to you skin, is that it protects your clothing through several wash cycles. Thus, one treatment can keep you clothes fighting mosquitoes for several weeks.
Check the product for specifics about how long its protection will last.