How many times have you ever picked up a whiteboard marker pen, and found that it is dry? And the next, and the next?
So, make them with a clear plastic barrel. If they are dry, then the colour inside is different.
Alternatively, line the inside of the barrel with an indicator for alchohol.
Plus you could tell the correct colour when someone has put the wrong cap on.
-- Ling, Mar 16 2004

I thought they're usually filled with a "felt" wick always soaked with the alcohol.
-- FarmerJohn, Mar 16 2004


Usually soaked with alcohol, until the alcohol evaporates. That's the problem: they dry out all too quickly.
-- Ling, Mar 16 2004


I've seen marker pens with clear channels in the case, so you can tell the level. But most markers use a felt wick, and you cannot it is empty by merely looking at it.
-- DrCurry, Mar 16 2004


Most whiteboard markers I've seen don't use alcohol. They instead use some rapidly-evaporating volatile hydrocarbon that gives me headaches and makes me lose anything that may remotely resemble an attention span. Just walking into a room where these markers are in use makes me go into a near-trancelike state.

I'll (+) any idea that gets rid of that stuff. Bring back regular chalk boards, I say! This idea doesn't have anything like that, so my vote stays neutral.
-- Freefall, Mar 16 2004


They can make tooth brushes that change color to indicate wear. Felt pens with some indicator for empty should not be too hard.

[Freefall] I love the smell those pens, but chalk makes me sneeze and my eyes tear. I could agree to water based pens, but never to chalk.
-- kbecker, Mar 16 2004


[+] because so many people have said "soaked with alcohol" I'm thinking this is the start of another good idea.... >:)
-- not_only_but_also, Mar 17 2004


[DrCurry], the felt wick gradually dries out (there is no liquid level). The idea is that, as it dries out, there will be a change in colour from dark to light.
[Freefall], the other solvent is called xylene? If you lose your attention span, maybe you should call them "bored" markers (groan).
[newser], embarrassing because you should have checked them before that important presentation to the board of directors.
-- Ling, Mar 17 2004


But those magical school-boy moments where the teacher tried to write something on the whiteboard with a dry marker, and then tried all sorts of medieval hocus pocus to get it to work again, will be lost forever.
-- spiritualized, Aug 15 2004



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