I had a problem cleaning my transducer as it was covered with hard tube worm casings (see photo). Before attempting fairly draconian cleaning measures, I bowed to my wife's insistence that we tried doing things HER way first which involved cola. She told me (aided and abetted by my 17-year old son who thinks he knows everything) that the combination of the phosphoric acid and effervescence of the carbon dioxide would neutralise the calcium carbonate of the hard shells so they can be removed.
So I bowed to the pressure and bought the 2-litre cola bottle from Asda for a whopping 18p (yes, that's right!) and put a freezer bag around the transducer and poured the bottle of cola into the bag. The cola fizzed and after 5 minutes in the bubbles all of the casings could be removed from the transducer with a finger nail (which my wife kindly volunteered).
Anyway just thought I would share this with everyone and I am obliged to, once again, remind you that is was her idea and she's always right!