It really depends on the quality of the coal. If it has even a moderate amount of sulfur, than long term you are looking at the sulfur reacting with water in the air to make sulfuric acid. I've seen old coal balls in storage cabinets that have a yellow coating on the surface from the sulfur, and these tend to crumble easily as well as reacting with other objects stored near them.

On Thu, Aug 22, 2013 at 8:12 PM, Lissa Kramer <[log in to unmask]> wrote:

We have a vintage coal car on display outdoors with a roof built over it. We have access to some coal and would like to add it to the display, but are concerned about what kind of degradation the coal may cause to the wood over time. Does anyone have any ideas about this and/or how we could display the coal in the coal car without causing degradation?

Lissa Kramer
Programs Coordinator
Issaquah History Museums

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-L.

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