Thrifty, Hamilton.

An ‘Awesome’ brand of calcium lime and rust removal is available in a green bottle (US 32 fl oz – 946 mls to us) selling for between $3-5 at some $2 shops, The Warehouse or Bin Inn. Just as good as more expensive brands. Worked well for me – I got rid of the white spots around my shower head, cleaned up the base of my taps, and removed a rust stain in the toilet bowl, all for the princely sum of $5 – and I still have 3/4 of a bottle left! As I’m flatting that is about all I’m prepared to spend.