She's a beauty! ONLY mechanically clean it with a toothbrush, wooden toothpick or the Andre's pencils, who are sponsors here. You can get them on Ebay. DO NOT USE ANY LIQUID and of course not water. You'll ruin it. After done, you can lightly brush it with a 50/50 mix of Elmer's glue and water.
1970 COMPASS-
WHITES SILVER EAGLE-
WHITES DFX, 4X6DD COIL, 6X8DD COIL, 950 COIL, 10X12SEF COIL-
GARRETT PRO POINTER AT, GARRETT AT PRO , MINELAB EXPLORER SE with 8.5x12.5 Cors coil
Congrats on your find as well as having the restraint not to immediately clean your button up. This forum is full of knowledgeable members who selflessly give their knowledge, and they didn't let you down.