Showerhead Nozzle Limescale Remover Cleaner 1L 5 "Surprisingly good" Lynne 17 August 2011 As i didn't have a very deep sink, I figured this wouldn't work that well. I submerged the worst of the shower head in the liquid (used the whole bottle) and left for 20 minutes. The 4 blocked nozzles in the shower are now working perfectly. I really didn't think it would work, as the head wasn't submerged enough. If you have a deeper container, you could probably submerge and keep some liquid. *bottle states it can't be kept once opened but slip of paper included says this IS OK to do. A note from the team Thanks for placing your review. The packaging may state use within 4 weeks after opening. It can be used after 4 weeks but it may change colour if exposed to sunlight. This does not impair the effectiveness of the product.