Mayday: my tube cap is stuck

For oil colours that you don’t use often, the cap may get stuck to the neck of the tube. You generally find out about this problem in the middle of a painting session. You are eager to carry on, you twist the tube cap with all your strength, the soft metal of the tube bends, wraps and the tube burst open (and the cap is still firmly on).

With the cost of oil paint, there must be a better way to solve this issue. Here is a trick my father tought me years ago:

• Take a jam jar or any recipient that can contain very hot water. 
• Put the kettle on. 
• Pour some boiling water in the jar and dip the tube upside down in the hot water, making sure that the cap is below the water line.
• Leave it for a few minutes. 
• Take a rag or a paper towel and unscrew the cap. If you cannot do it, put it back in the water.
• When the tube is open, remove the old paint around the tube mouth and the inside of the cap with a palette knife.

The hot water helps to soften the paint, even if it is oil painting. I believe the heat has also an effect on the metal of the tube, although I haven’t got scientific evidence of this. All I know is that this is an effective way to open old paint tubes.

It works for all paint tubes: oil paint, gouache, watercolour.

You can also hold the tube under the running hot water, but you end-up wasting litres of water.


Two final remarks:

1. Check your tubes from time to time. It’s not when you are out on a field trip that you will be able to use this method. 
2. Use a jam jar that you are about to recycle. Do not re-use the jar for aliments. Paints contain dangerous compounds like lead, cobalt or cadmium that are harmful when injested.

Related articles

• How to open a stuck tube of oil paint
• Cleaning your brushes for oil painting

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