During a recent tidy-up I found some double-sided copper clad fibreglass board. As it had been lying for many years it was very dirty and tarnished but otherwise OK.
Rather than just throw it away, I decided to clean it for use in the future.
My usual method of cleaning copper clad board is to use a Brillo pad (a steel wool pad containing soap, intended for cleaning cooking pots etc).
I started with the Brillo pad and it was hard work as the tarnish was very heavy.
I then remembered a TV advert for a cleaning spray called "Cilit Bang", the advert shows a tarnished copper coin which has been dipped in said liquid, it was shiny again.
So I sprayed the boards with Cilit Bang and waited for a minute or so, gave them a quick scrub with the Brillo and the result is clean copper clad board with a lot less effort.
So, all I need to do now is to make something using the shiny clean boards and not let them sit for another 15 years or so!
JimB