Blue Tokens are a legacy currency that is no longer obtainable. That means unboxing duplicate skins from cases does not generate Blue Tokens anymore. Instead, you can have multiples of the same skin, which can be used in Trade Up or Community Marketplace.

If you happen to receive a duplicate of an item that cannot be used in Trade Up, such as an Epic or a Legendary item, do not worry since you can sell those in the Community Marketplace.

Please note that item loadout crafting with Blue tokens was discontinued in the 1.46 release. However, there might be more options for using the remaining Blue Tokens in the future.