just opened up a crappy Esteban guitar to restore and giveaway to somebody who needs it. Remove the pic card and the back cavity and this white crud is all over it. Doesn't look like any fielding material I've seen and I'm kind of concerned. Has anyone seen this before and a van idea what it may be?
https://photos.app.goo.gl/Taj1dLnFBHV4GjcL8