On Tue, 5 Jul 2011 10:36:34 +0000 (UTC), "steve robinson"
wrote:

Huge wrote:

On 2011-07-05, Dave Plowman (News) wrote:
In article ,
steve robinson wrote:
The reason paint goes off after being opened and used is the
large quantity of new air when you replace the lid.

Your better dropping a peace of plastic in the bottom

Or fill the space with some inert gas?

Store the tins upside down.

Makes no difference once the tin is opened and new air introduced.
Fill the can with CO2 before closing - no oxygen to react with the
driers in the paint. CO2 is heavier than air, so displaces the air and
stays in the can.
Storing the can upside down just puts the "skin" on the bottom