Brown marks
Hello,

Remove the brown tea marks from inside a mug by rinsing it in cool water then scrub in the inside with salt then rinse with cool water again. Works every time.
(Free pens 100, 101, 102 is still counting on, Fri 4 Dec 2009, 12:10, 7 replies, latest was 15 years ago)

Or simply a quick rinse with water upon finishing the beverage, then leaving to clean properly.
or not.
(TheColonel, Fri 4 Dec 2009, 16:27, Reply)

Or use a teapot
and the brown stuff lines the inside of the pot instead
( sandettie light vessel automatic New Twitter - @bollocksreally, Fri 4 Dec 2009, 23:18, Reply)

or use bleach (but rinse well after!)
(kitescreech still here, Sun 6 Dec 2009, 8:32, Reply)

or.
just use a different cup..
(danniekavanagh did nothing constructive on, Sun 6 Dec 2009, 15:00, Reply)

Or buy some white paint
and repaint the inside of your mug after every use.
(Paolo Nutini's Bikini Better than Frederick Fleet's optometrist, Mon 7 Dec 2009, 16:49, Reply)

Ha
I like my cup to develop a bit of an atmosphere..

Does that make me a bad person?
(Sir Clitherington Smythe offers him yourself., Tue 8 Dec 2009, 16:48, Reply)

I used to use caustic soda for this as any other method seemed to be too much hard work, oddly enough mashed potatoes and cuppa soup work nearly as well.
(Benzyl, Thu 10 Dec 2009, 19:23, Reply)