I know that you can sell your bitcoin to trade plattform like coinbase etc.. BUT you need to verify your identify, so it' s not anonymously.
How do you cashout your bitcoins anonymously then?
you can try purchasing gold with the use of bitcoin payment and having it shipped to some anonymous address, like for instance there are some countries with those machines used to deliver parcels, you have to enter the code and the parcel is yours. From there it is just a question of selling gold anonymously, which as I suspect differs from country to country.