Used corny keg, grey rough patches inside

[DSorenson]

I've been cleaning up and overhauling a (new to me) used ball lock corny keg. It's my first, but I am familiar with stainless steel- how to clean it, etc. It has only been used for soda.

My cleaning began with two day long soaks in oxifree (inside and out, right side up and upside down), taking off stickers, glue goo (only using glue remover on the outside), and finally today using bar keepers friend, inside and out.

The outside isn't polishing up quite like I would expect: it seems that this keg has had a lifetime of good service. I'm okay with that. Function over form, after all.

Here's my problem, though...

On the inside there seems to be "water" lines that look grey in color and slightly rough (enough to shred little bits of paper towel) and very similar grey patches.

There is no uniformity to anything. Some of the grey patches almost look like liquid drips... to the point where I'm not sure if they aren't signs of minerals precipitating out of the oxifree solution.

One more thing to note:
Today I realized my water softener has been out of salt for some time, so my oxifree soaks were in very hard water. I don't know if that means anything to anyone...

Questions:
1) what is it that I'm looking at? (sorry, no pictures)
2) should I worry about it, or just keg a beer and be done with it?
3) if I should worry about it, what do you recommend?

I've exhausted all my elbow grease I can muster for today.

 

[eluterio]

A few things, make sure you rinse out the oxifree well maybe even a scrub hopefully wont leave a residue behind and contaminate your beer.

As for the scratch thats unusual unless the previous owner, pespi or person, scrapped the crap out of it with something to cause this. I have a few from kegs that I got from pepsi and ive notice a few scratches but not as bad as yours. I wouldnt be to concerned about it as long as you do a long enough soak/wash cycle. I would switch to pbw that what I use and works great with kegs cleaning. The grey patches seem like stains unless its oily I wouldnt worry about it.

Absolutely make sure you buy new o rings for Dip tube, poppets, and lid.

hope this helps

 

[DSorenson]

New O rings: check. Those are going on as soon as I figure out what these grey patches are. They are not scratches, but instead feel like build up... or something like it. For the record, I have O rings for the dip tubes, posts, and lid. I hope this is what you meant instead of "poppets". From what I understand the poppets are the small spring valve assembly inside the posts.

PBW: noted... I believe this will eliminate concerns I have about oxifree and hard water. Still not sure if that is the culprit, but there is only one way to find out.

One last question:
Anyone ever use Starsan liquid to buff?
I know it's a mild acid, so I was thinking it could take off mineral deposits... should that be what this actually is.

 

[eluterio]

Yes you are correct I meant post. You know star San full strength might work! I would research how long the contact time would be but a really good idea!


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[USAFSooner]

Have you tried Bar Keeper's Friend yet?

 

[eluterio]

Not sure I would use bar keepers friend. Maybe hit lhbs and take it in and ask them.


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[sandyeggoxj]

I love bar keepers friend. I would use a soft sponge and bkf and polish the inside of the keg and then wash it again and you should be good to go.

 

[DSorenson]

...and finally today using bar keepers friend, inside and out...

Bar keepers friend was already used by the time of the original post. It is fine on any stainless steel.

Any other ideas are welcome!

 

[sandyeggoxj]

What about some acid #6 from 5 star?

 

[DSorenson]

Never heard of this... I must find enlightenment on the topic.

Would this be at all like using pure starsan?

 

[sandyeggoxj]

I forget what is in that blend. I use acid #5 for cleaning and passivation of stainless. It is phosphoric and nitric acid. Acid 6 was designed for kef cleaning under a co2 atmosphere. I'd ship you a small bottle of acid 5 but it can be a pain because it is hazmat. I buy it by the case.