A System for the Compleat Interior Management and Oeconomy [sic] of a Battalion of Infantry, Dublin.
(There was also and edition of 1776)
Of the arms and accoutrements, and the methods for always keeping them in the best condition
“A picker being often useful to a soldier, for cleaning the touch-hole of his firelock, in the firings, one of strong wire should be fixed, by a small chain, to the edge of his pouch-belt, under the front buckle, and as close to the pouch as possible, but never to hang it in view, as it might be troublesome, in raising the flaps of the pouch, to take out the cartridge."
As taken from: British Military Uniforms, 1768-1796, Hew Strachan, Arms & Armour Press 1975, p158