I don't remember the exact date we bought our thermoses but there are references on this post to them being about 10 years old in 2015. We paid a splendid bargain price for all of them - and they have been very well used over the years. In 2015 I looked at replacing the lid seals but that was shortly before our Great Cull, so thermos care was shelved. (While in transit we tended to use a small dual fuel stove for picnics as it was easier).
One thermos has seen more use in recent times, which prompted me to source new seals. When inspecting the lids, I remembered one was damaged - so I ordered two lids and two seals.
Total cost of the order, including postage, was just under $35.00. Not bad for 15-plus years of service!
I'll replace the seal on the undamaged lid and keep that one as a spare. After ordering the new lids, I decided to give the thermoses a spa treatment. Denture cleaning tablets were recommended for deep cleaning and I bought a 48-pack for $3.50 from Coles.
The method I found is to use two tablets per two cups of capacity. As the large thermoses are 1.9 litres, I used 8 tablets for each of those. Erin's thermos is smaller than the other two, so I used 4 tablets for it. I dropped the tablets into the empty thermoses and then filled with hot tap water. The effervescence caused fluid to bubble up, which was fun! I stood them all in the sink till they'd stopped frothing. They were then left for 4-5 hours before being emptied and rinsed.
Some people fill their thermoses with pre-made tea or coffee, which causes staining. We only carry hot water in ours (preferring to make drinks on site with provisions carried in our beverage case) so they didn't really need deep cleaning. One had a little residue on the inside base, possibly water sediment - so had been sitting in the cupboard, beside the broken lid. My bottle brush was too short for effective scrubbing (and didn't fit the neck of Erin's), so I gave each thermos a second treatment and left them to soak overnight. Bunnings had a Sabco drink bottle cleaning set, which worked wonderfully for all three. There were just eight tablets left in the box, so I've given our two food flasks a bubble bath, too!
Erin's thermos was purchased second-hand in late 2014 for the amazing price of $1.00 or $2.00 from a market seller who was packing up at the end of the day. We'd cleaned it after purchase, with hot soapy water and perhaps some bicarb soda. Erin can't remember ever using it. I had many denture tablets available, so cleaned it also. As it happened, hers did benefit from the thorough foaming treatment. (It has a narrow neck opening and was more awkward to work with).
