Cleaning stained stainless steel flask

Try bicarb and boiling water, left overnight then tip out and rinse.

Or soak the lot in a dilute bleach mixture overnight. It won't leave a smell if you rinse it properly afterwards.

I second several teaspoons of bicarbonate of soda in boiling water, left overnight. Works a treat when DH cleans his up.

Bicarbonate does work; if it's very stained use Milton, or Chempro sterilising solution used for cleaning wine making equipment. Wilkinsons sell it. A little goes a long way.

It's utterly grim isn't it? DH says it adds to the flavour of his coffee but I think it's a health hazard ?
I tried everything from bleach to Steradent, bicarbonate and boiling water to kettle descaler, bio washing powder to Milton tablets....the only stuff that made any impression was liquid for stained teacups but I have no idea where I got it from (it was in the back of the cupboard!)

The main problem is that DH doesn't clean it properly so it builds up to a disgusting layer

Oh! I thought I was talking to you there Greyduster. But it's a new poster (I think) Greymary.

Remember Granny Grey, jingl?

Well thank you one and all. I am now using the bicarb and hot water overnight remedy. I can report back on results tomorrow if it is of interest?

jingle hello . I am new here, not much of a poster more a lurker, but apologies if I haven't introduced myself. Hello everyone.

O/t I know, but I do enjoy reading and commenting (to myself in private) on the many threads here.

I'm not even officially a grandparent yet but ever hopeful. Some step grandchildren in the picture at the mo.

Thanks for the tips everyone.

Hello, GreyMary. You are very welcome here whether or not you have any grandchildren. Hope the flask recovers. The press button lid will be more difficult than the actual flask. I mostly just put boiling water in the flask and take instant coffee in a little jar and milk in an insulated bag so that the flask stays clean.