Pet allergens help!

I make baby blankets for friends for now but would like to get into more of selling them. I live with cats which I'm aware some people may be allergic to, and do my best for them to not come in contact with my fabric but I want to be sure the blankets can be safe for those with allergies! Should washing them in dreft detergent help? Should I put a disclaimer for the buyer to wash first with their choice of detergent to prevent allergens? Any tips?