I found this:

For silk, wool and delicate items, I recommend soaking them in a bath of
water and Scented Vinegar. Vinegar is known for its powerful cleansing
properties that fight stains, buildup, odors and germs, so it will help
rid your clothing of that potent mothball smell. The amount of vinegar
added to the bath and the temperature of the water will vary according
to the number of items being washed and their fabric composition.

You can also add the vinegar directly to the washing drum (top loaders)
or the detergent dispenser (front loaders) and run a wash cycle without
detergent or softener. Follow the vinegar wash with a normal wash cycle.

When treating more durable fabrics such as cotton and linen, you can try
soaking the items in a bath of hot water and All-Purpose Bleach
Alternative for roughly 30 minutes. The All-Purpose Bleach Alternative
is a nontoxic, fragrance-free alternative to chlorine bleach that is
color friendly and will work to remove the odor as well. Treat the soak
as a pretreating procedure and follow with a normal wash cycle after its
completion.

Tip #1: Stuff everything with newspaper & put in tightly sealed garbage bags for two days to a week. This should do it.

Tip #2: Also, try cedar chips. I put them in the drawers
of an old dresser that had been in an abandoned cabin that smelled
strongly of mouse droppings that none of my washing had been able to
remove. The cedar chips took it all away.

Tip #3: There's a spray product called AtmosKlear that
claims to eliminate any odors if it's sprayed directly on the source of
the odor. We've had remarkably good luck using it on stinky shoes,
pitted-out shirts and carpet that's been urinated on by cats, among
other things. It's not cheap by any means, but IMO it pays for itself by
allowing us to save items that would otherwise be ruined because of the
odors. Not sure how it works on mothball odor, but it might be worth a
try.

Hope this helps

Sometimes coats and other outer garments are treated with water resident substances that washing or vinegar or other things could remove. What does the label say? I'd try to be patient with using just fresh air, it should go away before long.

I just googled care instruction for London Fog raincoats. They recommend dry cleaning or washing.

Why not just wash it unless this particular one need tone dry cleaned? I don't think airing it out will solve your problem.

I don't suppose you have one, but do you know of anyone who has an ionizer? They work well at removing odors. Having it out in the rainy weather is a good choice but don't expect it to air out overnight. Some good freezing cold weather should be coming your way soon and cold can help deodorize too.

Some like the sprays like Febreze, but I don't like them. I'd be cautious about vinegar baths since it is acidic. Not sure if it would affect the fabric or not.

Otherwise, keep airing it out. Newspaper, baking soda, charcoal briquettes and even coffee grounds are good odor absorbers. The problem you have is the smell is going to be permeated throughout the garment, in the lining and everything.

Good luck. Keep us posted.

dry cleaners

Thanks for all of the suggestions! It's out on the line again today, and it's a cool damp day. I checked the label and it can be machine-washed.

It can hang outside for several days, as there's no significant snow-fall forecasted.

With regards to the coffee grounds.....can used ones work, or does it have tobe fresh? I can picture washing the coat anyway after using baking soda or grounds.

I've kept it on the line for 3 days, day and nite. It's been blown, and rained and snowed on. I'll bring it in today and hang it to dry and see if it's better. If not.....out it goes again!

I've never used old coffee grounds, but I can attest to it removing odors. Great stuff.

Ozone treatment (many furriers and fur storage places offer it,) or just continuing to put it outside.