Martexin reproofing wax. Operating instructions on the can.
Archival Clothing endorses waxed cotton because it's a rugged, natural, water resistant fabric that requires only wax reproofing to maintain its finish. Waxed cotton users should know how to reprooof their jackets, hats, and bags. Both Filson and Barbour offer factory reproofing services but we recommend performing the work yourself (at least once). Reproofing waxed cotton is relatively easy and personalizes the care and maintenance of your garment. Even if you live in the desert, you should establish a reproofing schedule for your waxed cotton. Reproofing extends the life of waxed cotton and prevents it from developing the folds and wear lines that often lead to holes.
I do my reproofing in August so I can move the work outdoors.
Basic tools: wax (warmed), water, sponge, blow dryer (or heat gun). If you're using our 1.5 ounce tin, spoon some wax into a bowl and heat briefly in microwave. Some people recommend using Filson wax, say, with a Filson product, but I've switched between several brands of wax treatment (Filson, Barbour and Martinex) with the same results. I will concede that for a full reproofing job on a jacket, the larger tins of Barbour reproofing wax are easier to heat in a double boiler.
Dab off dirt with a moistened sponge. Do not use soaps or detergents.
Reheat surface of item with blow dryer to melt the wax into the fabric.