Personally, I'd take them both to the sink and use as hot of water as you can stand and rub between your fingers. It sounds harsh, but it's really very safe on copper.
If that makes you unconfortable, try soaking in distilled water first. Next, soak in acetone and then, finally, soak in xylene.
If that makes you unconfortable, try soaking in distilled water first. Next, soak in acetone and then, finally, soak in xylene.























