Well, it could be Zinc Anodes or some other metal. We will wait for your photos.
You can also drill some shavings and bring those to
McPhar Geophysical Services for testing (see contact details below).
BJS Compound, 1869 P. Domingo Street,
Makati City, Metro Manila, Philippines
Telephone No.: +63 (2) 896-1656
+63 (2) 896-1681
+63 (2) 896-7973
Fax No.: +63 (2) 890-0290
E-mail Address:
lab@mcphar.com.ph