Scraper Sharpeners
The cheapest tool on the bench that makes the biggest difference to a wax job. A plexi scraper dulls after a few pairs, and a dull scraper smears wax into the structure instead of lifting it off.
A sharpener guides the scraper across a blade at a fixed angle, squaring the edge in a couple of passes. Doing it by hand with a file almost always puts a bevel on, which is worse than leaving it dull.
Sharpen far more often than feels necessary — a scraper that still looks fine will cut noticeably better after one pass. Most tuners do it between every pair.
See wax scrapers, and the rest of our waxing equipment.