I have a strip rectangular balsa wood (approximately 2mm thick and the dimensions of such a longitudinally halved Postcard) taken, roughened with 80-grit sandpaper across, then over it rubbed the block and leveled the crumbs with a straight knife back with a lot of pressure on the timber. Then again briefly over it gone with the hot air gun and melted on the timber (which is certainly more than a candle) and holds everything perfectly.
The removal is quite high, the paste even raises an already liberated from the ridge knife a new burr, which can however be easily removed when you pull the blade gently through a cork or a piece of wood. After the cutting is however also really razor sharp, in my relatively soft Solingen knives and even an IKEA Slitbar knife.