Yea, most of the time, if I find a feather from a bird I know (for a fact) doesn't have any harmful bugs, viruses, etc, i'll just preen the feathers loose of dust and dirt with my fingers like that. So long as you don't use your nails - which strips the "velcro" off of the feathers whispy parts...
Just used each of these methods on some crow/raven feathers I found throughout Oakland.
Dawn seemed to be ok on strong feathers, but I noticed it did Really help when I took the time to gently reshape the feathers while they were still damp. And as far a drying, since I don't have a blow drier...
How to Clean and Sanitize Found Feathers
“Dry” Cleaning Method
Soap and Water Method
Additional Tips and Advice
Feathers are delicate and require special care when cleaning.
There are two types of feathers, contour and down.