Handling the dry ice carefully (newspaper works well), break off a few large pieces with a hammer and a sharp object (about half of the block to start off with). Place the pieces of dry ice in a kitchen towel and wrap it with another. Using the hammer, bash the ice into even smaller pieces until it starts to become a powder. Using the towels, tip the pieces of ice and powder through a sieve into a bowl. Don’t use the bigger pieces that don’t pass through the sieve, rather bash them again.
It will start ‘smoking’ heavily, but once the ice has been absorbed you’ll be able to see the mix. Keep on adding dry ice powder until you’ve reached a sorbet consistency. You may need to add several batches of ice powder.