Back before I found compressed dehydrated sponges in the painting section of my local crafts store or gourmet kitchen sponges at a local kitchenware store, I wanted to put some sort of sponge in my pocket tin, so I resorted to cutting a piece out of a local supermarket's sponge cloth.
I put it in my PSK...
...and all seemed well.
But, when I opened my tin for annual inspection and maintenance, I found...
...that something about the spongecloth had damaged the aluminum foil, merely by prolonged contact.
Please note that all of these pictures were taken after unpacking. The aluminum foil residue you see in the first image was not there when I packed it; nor was the rust you see in the second image. The rust, BTW, came from a safety pin, which was also ruined.
So...
The first lesson might seem to be:
This brand of sponge cloth is hard on metals. Don't use it.
The second lesson might seem to be:
Be careful with aluminum foil. Over time, and with
pressure, it can be unexpectedly damaged, even in storage.
And the third lesson might seem to be:
We should all periodically unwrap, untape, open and
inspect all contents of any kits, tins or packages
we use, carry, store or (perhaps especially) sit on.
In a reply to the above post, "bones" wrote:"Could this have been electrolysis between the safety pin (iron) and the foil (aluminium)? (i.e. nothing to do with the cloth?)Clever thought. That possibility hadn't occurred to me."Just a thought - wrap the foil in a small baggie or cling wrap."