Do you remember the old fashion TANG. It works but its called orange crystals now. Put half package to full kettle of water, keep lid up so that kettle can continue to boil for 2 mins. Boil kettle with clean water a couple of times to get rid of the orange taste. Wipe out any scum or residue with paper towel.If your kettle is plastic inside it may discolour from the orange colour but it remains safe to use
Lorraine Thistle, June 2005