Everyday door handles are often hotspots for bacteria, public handles especially. Because of the frequent and inevitable use of most door handles, it can often be expected that bacteria are present.

The Handle System is the Corporation for National Research Initiatives's proprietary registry assigning persistent identifiers, or handles, to information resources, and for resolving "those handles into the information necessary to locate, access, and otherwise make use of the resources".

The cocking handle, also known as charging handle or bolt handle, is a device on a firearm which, when manipulated, results in the bolt being pulled to the rear, putting the hammer/striker into a spring-loaded ("cocked") "ready and set" position, allowing the operator to open the breech and eject any spent/unwanted cartridge/shell from the chamber, and then load a new round from the magazine or belt if required. By opening the breech, it also helps the operator to verify that the weapon's chamber is clear of any rounds or other obstructions; to clear a stoppage such as a jam, double-feed, stovepipe or misfire; to facilitate moving the bolt back into battery, acting as a forward assist (but not necessarily); and to release a bolt locked to the rear by a catching mechanism on a firearm equipped with a "last round bolt hold open" (LRBHO) feature.