As multiple people have pointed out, there are worthy causes that will accept them, such as women's shelters. There may also be people in your life who would appreciate them or who may have their own worthy causes, and may have uses for partially used kits - I understand that you will spot many vendors at the market in My Tho using Air France amenity kits as wallets thanks to my cleaning lady.

If you don't want the kit, don't break it open and give it back to the crew for them to stow.

There are many ways for them not to go to waste.