Softening old tins of polyurethane

[Timothy Murphy]

Is there any way of "thinning" old tins of polyurethane varnish that have not been sealed and have gone hard?

[Michael Mcneil]

You mean one that will give you a cheaper alternative than buying a new tin, yet allow you to apply a nice finish and have it last as long as the good stuff?

Or do you just want something you can throw at the bloody fool responsible for leaving the tins open, without killing them?

[Timothy Murphy]

Yes - though it's not so much saving money as not wasting the half-tin that's left.

I assume from your response that there is no solution (pun intended).

[The Natural Philosopher]

no.

[Michael Mcneil]

Quite. They are like epoxy resins. They react with oxygen to form a plastic coat. I used to put turps or whatever thinner -just a few drops on top of part tins and turn them upside down.

It kept them a little longer and any skin formed on the bottom. The tin was properly sealed too or went to hell noticeably quickly.