Help clean 5 gallon glass antique water jug / carboy

[Brewmaster_n00b]

I bought a 5 gallon antique glass water dispenser jug or "Sparkletts" container at a garage sale. Needless to say it was dirty and needs a good cleaning, I was able to remove a good bulk of the gunk with regular soap and water sloshed around for about half an hour. But there is a fine buildup on the bottom on the inside. How can I go about cleaning this? It's stuck on there pretty good. I soaked 2 fl. oz star san and 5 gallons over night and now I need to get a little bit more abrasive. Any ideas are welcome, thanks.

 

[Mojzis]

I use cheap oxyclean from dollar general. 1-2 scoops in a warm soak for a few hours will work. If you have hard water and scale builds up on the glass, an acid such as star san or vinegar will remove it.

 

[Shred]

Soak it in PBW or Oxyclean. If there is any residue, try making one of these (my project for tomorrow):
DIY Carboy Cleaner