Before use, soak the casings for 1-2 hours in cold water to remove salt and make them pliable. Drain but do not dry them.
Clean and open each casing by attaching one end to a tap and running cold water through it. Tie each casing with string at one end. Attach the open end to the base of a funnel. Slide the casing up the funnel until the closed end of the casing is reached.
Work the sausage filling through the funnel into the casing. Do not pack the filling too tightly or the sausages will burst as they cook. Twist the casing at intervals as you go, to make a string of sausages. Tie the casing with string at the end.