Milk deposits on the inside of a Thermos

Howard

Lifer
Oct 14, 1999
47,982
11
81
I accidentally left whole milk inside my thermos over the weekend and now there's some hard crud on the upper section on the inside (just underneath the neck where I can't reach in with a sponge on a stick). Any ideas? I tried boiling water and vinegar and neither worked.
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
Will that dissolve the deposits? And won't a boiling bleach solution damage the stainless steel inside?

forgot to mention that part
 

CallMeJoe

Diamond Member
Jul 30, 2004
6,938
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Dishwasher detergent and hot water. You'd be surprised what a good soak in dishwasher detergent will remove.
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
Dishwasher detergent and hot water. You'd be surprised what a good soak in dishwasher detergent will remove.
I already soaked it (full to the brim) in hot soapy water last night.

I don't know why only the bottom half is clean, though.
 

CallMeJoe

Diamond Member
Jul 30, 2004
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I already soaked it (full to the brim) in hot soapy water last night.
I don't know why only the bottom half is clean, though.
Not regular dish washing detergent, dishwasher detergent (Cascade, Electrasol, etc.).
 

waggy

No Lifer
Dec 14, 2000
68,143
10
81
you could have let it sit a little longer and just had it as cottage cheese!

oh and joe is right that should do it. also after that run it through a dishwasher if it has the sterilize option or whatever its called.
 
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Perknose

Forum Director & Omnipotent Overlord
Forum Director
Oct 9, 1999
46,890
10,712
147
Damn. Now I gotta go buy me some...

And . . . if it doesn't work the first time, repeat and let it soak looooooonger. Time is on your side, but you have to have the sometimes nearly infinite patience to let it work for you.
 

spidey07

No Lifer
Aug 4, 2000
65,469
5
76
CLR. Let it soak in it for a good while and it will remove it. Vinegar isn't strong enough. A base like soap won't do any good, you need something to dissolve the calcium (acid).
 
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bmaverick

Member
Feb 20, 2010
79
0
0
Not regular dish washing detergent, dishwasher detergent (Cascade, Electrasol, etc.).

Cascade with some water, let it sit overnight is a must. I had something similar with liquid yogurt in a thermos bottle before that sat all weekend in my locker.
 

Tiamat

Lifer
Nov 25, 2003
14,068
5
71
Invert it into a ultrasonic-sonicator with water bath.

If you do not have access to a sonicator, how about filling it partially with soapy water and spherical beads (like metal or glass beads similar to ball-bearings) and rotating at an angle to try to scrape it out with the beads.
 
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BoomerD

No Lifer
Feb 26, 2006
66,404
14,798
146
Will that dissolve the deposits? And won't a boiling bleach solution damage the stainless steel inside?

forgot to mention that part

It should dissolve the milk ring...and it SHOULDN'T hurt the stainless steel. For a quart bottle, I'd use 3-4 tablespoons of bleach with the rest boiling water.
I've bleached stainless thermos bottles for almost 40 years...and never hurt one.

I remember one time, I came home after getting laid off for the winter...and forgot my thermos bottle in my pick up...and it rolled under the seat, where it stayed all winter. When I found it in the spring...the coffee had molded and turned pretty nasty. I soaked it in a bleach water solution for a week...sparkling clean.

I sold it in our yard sale. :p

(but it sure LOOKED good.)
 

spidey07

No Lifer
Aug 4, 2000
65,469
5
76
Boomer, I thought you were a reefkeeper like me. You know that isn't going to get the calcium carbonate.
 

BoomerD

No Lifer
Feb 26, 2006
66,404
14,798
146
Boomer, I thought you were a reefkeeper like me. You know that isn't going to get the calcium carbonate.

:biggrin: Perhaps, but it will dissolve the organics in the milk...I guess he could also try muratic acid...but it's a bit less forgiving than bleach.