When you buy plywood, chipboard, OSB etc from B&Q or other timber supplying emporia the items usally have a sticky label placed in the middle of the sheet - with glur of the "shit to a blanket" variety . . .
I've discovered, courtesy of YT, that gentle heat from a heat gun (or even a hairdrier) and gentle scraping eases the label from the surface leaving minimal glue residue which can then be gently sanded away.