Cleaning mud dauber nest stains from sails

[Stuart 28-2]

In North Carolina, and elsewhere I'm sure, mud daubers like to use the abundant red clay. Anyone found a successful method for cleaning them off?
Warm water with Dawn and elbow grease makes only a minor improvement.

 

[Christian Williams]

Try some bleach. It;s OK on Dacron. Mild solution. Rinse after action such that solution doesn't bleach the decks too.

 

[Frank Langer]

Bleach can leave the sail a bit yellow, so be careful, rinse quickly and well. Perhaps try a weaker bleach solution first, mixed with water.
Frank

 

[Captain Pete]

I have had some good results on dirty dacron sails using Oxyclean from the laundry room.

 

[Christian Williams]

come to thnk of it, the red is probably iron oxide. try some oxalic acid, as in rust remover for toilets etc.