Cleaning a used sump

[CEverii]

So whats the proper way to go about cleaning a used glass sump. It has this thin white layer of film on it (assuming its salt residue). I tried using a razor and water. It works, but barely. Would take WAY to long to do the entire thing. I didnt want to use any cleaning solutions but I might have to. Any suggestions?

 

[BigJim]

White vinegar is your friend.