As part of a recent homeowner project, I applied a file to dull pruning saw that, as far as I can recall, Came With The House™ and has been untouched for decades:
Yeah, that’s a lot of steel filings; it was really really dull. Notice how they’re neatly lined up toward the blade?
It looks better from the side:
Despite my crude technique, it cuts wood like a hot knife through butter.
The Smell of Molten Projects in the Morning 