Hi MO,
First of all, I am no expert on handling "fresh" tying materials, but this is the method I have used over the years when hunter-friends have given me gifts of various furs and feathers.
1) thoroughly clean and wash items in a good quality pet shampoo with flea control and follow that up with a second washing with dawn dishwashing soap.
2) dry on top newspapers or a towel on top of clothes dryer (a warm heat as opposed to hot heat) or in sun for as long as it takes to be bone dry.
3) When dry, put items into an isolation box (tupperware air tight or rubbermaid) and sprinkle thoroughly with Borax from laundry department of local supermart and leave alone for one to three months.
4) When items have been stored for at least a month or longer, remove them from isolation box and wash again in pet shampoo/dawn soap folowing same method as above. Run isolation box through dishwasher on the antibacterial cycle and then use to store the items with a generous supply of mothballs away from other store bought professionally processed tying materials. I have never had a problem and some might consider this as "overkill" but I do not take chances when I have a large collection of expensive tying materials.