You're welcome.
About cleaning your brass button (not pewter)... I use common household ammonia -- plain ammonia, not "sudsy" or any other formula. Ammonia can be too harsh for heavily encrusted or heavily corroded buttons, so DO NOT use it unless you are absolutely certain the button can withstand it. As a precaution, dilute the ammonia 50/50 with water. Put the button in it, face-side up. Let it sit for 90 seconds, remove it, dip a toothbrush's tip into the ammonia and scrub gently. Then rinse the button thoroughly under running water, to get rid of every trace of ammonia on it. If further cleaning is needed, put the button back into the ammonia for another 60 (or 30) seconds, and repeat the gentle scrub with the toothbrush's tip. Don't forget to rinse thoroughly! It's very important not to overclean, which is why I do it in stages.