On Thu, 9 Feb 2012 08:03:55 -0500, "Robert Green"
wrote:

Linseed oil is notorious for self-combustion

Linseed oil MSDS

Flammability of the Product: May be combustible at high temperature.

Auto-Ignition Temperatu 343°C (649.4°F)
Flash Points: OPEN CUP: 222.22°C (432°F).

....

Precautions:

Keep away from heat. Keep away from sources of ignition. Empty
containers pose a fire risk, evaporate the residue under a
fume hood. Ground all equipment containing material. Do not breathe
gas/fumes/ vapour/spray. Avoid contact with eyes Wear
suitable protective clothing If you feel unwell, seek medical
attention and show the label when possible.

Storage:

Keep container dry. Keep in a cool place. Ground all equipment
containing material. Keep container tightly closed. Keep in a
cool, well-ventilated place. Combustible materials should be stored
away from extreme heat and away from strong oxidizing
agents.

http://www.sciencelab.com/msds.php?msdsId=9924500

By that, even the empty containers pose a fire risk...