¼" Jack abrasive cleaning tools. These are perfect for cleaning contacts inside ¼" jacks on various audio equipment, such as Reel to Reel machines, amplifiers, guitar inputs & any other ¼" jacks.
The tool itself will normally last between 1-3 uses (depending on jack dirtiness). Supplied as a pack of 3 softer tools and 1 aggressive metal tool. 
See the videos for example.
Free postage.