Urgent question about copper jam pans

[Stillcounting]

I'm in the middle of a jam-making session

I've rejected my old copper pan because I can't seem to get it clean. I wash it and wash it, and the water appears clean, but then it leaves black smears on the t-towel ...I daren't use it for fear of tainting the fruit.

Does anyone know what to do please?

I'm using smaller stainless steel pans at the moment but I want to make a larger batch tomorrow and need my large copper pan for that.

Any advice gratefully received!

Anyone have any ideas pls?

I got this witch couldron jam pan for my sister.

Thanks very much Lizziemun - am rapidly coming to the conclusion that I am going to have to invest in a new pan - and that example looks particularly good ...

Back to my eye of newt ....