Cleaning deposits off of Filter

[shamu]

I have an Aqua Tech 30-60 Filter for my 55 gallon tank, I recently bought this tank used and it was pretty clean but it has white hard deposits on the plastic parts of the filter and lights, it looks like some kind of hard water build up, what can I use to get it off, I tried using a toothbrush but that didn't work and I of course don't want to use any cleaning product, any suggestions?
Thanks

 

[revchristinejday]

My guess is that they are hard water build up. I have been not be successful in removing old stains. But new stains can sometimes be removed with vinager: soft cloth with it on, rub rinse with treated water...Good luck