Oilskin coats are made from cotton covered in an oil and wax coating. Although the oil and wax makes the coat wind-resistant and waterproof, oilskin coats can still develop mold, mildew and stains that cause odors. Since these coats cannot be washed in a washing machine or dry cleaned, they must be washed by hand. The most effective way to remove odors is to clean off the dirt, grime or mildew causing the odors and reproof the coat. The trick to cleaning oilskin coats is to use mild cleaning agents to avoid damaging the fibers. Both spot-treating and hand-washing are effective methods to clean these coats and remove odors.

Wipe off any visible dirt, grime or mildew from the surface of the fabric, with a sponge and cold water.

Remove any stubborn stains with a soft-bristled brush. Rinse the area thoroughly with a wet sponge to remove any leftover residue.

Rinse the entire coat with cold water from a garden hose, shower head or faucet to wash away any remaining dirt or grime. Hang the coat in a dry, well-ventilated area and allow it to dry overnight.

Add a capful of mild laundry detergent to a large sink of cold water. Place the coat in the soapy water, and swish it around to thoroughly saturate it.

Allow the coat to soak in the soapy water overnight.

Remove the coat from the soapy water, and drain the sink. Rinse it with fresh cold water, by refilling the sink and swishing it around. You may need to rinse it more than once, until no more soapy water remains. Hang the coat in a dry, well-ventilated area and allow it to dry overnight.

Lay the coat flat. Run a hairdryer over the fabric to warm it up and make applying the oilskin dressing easier. Place the can of oilskin dressing in a saucepan filled with hot water to warm it.

Apply the oilskin dressing to the coat with a clean cloth, using a circular motion. Apply extra wax to the seams of the coat to prevent leaks.

Wipe off any excess oilskin dressing from the surface of the coat, with a clean cloth. Hang the coat in a dry, well-ventilated place and allow it to dry overnight.

Reapply the oilskin dressing to any missed spots, after the coat has dried.