An ashtray is a receptacle for the safe depositing of cigarette by-products The easiest way to discover if something is an ashtray is by judging its proximity to the nearest smoker. If the object is more than five feet from the comfortably seated smoker, that object is an ashtray.
Ashtrays share the same qualities of inverse magnetism as remote controls, soap in bathwater and postage stamps. The reason for their aversion to the vicinity of humans is unclear, and this behaviour has had an problematic effect on the lifestyle of smokers for centuries.
For this reason many smokers have experimented with alternate forms of ash storage.
Cups are the safest alternative to ashtrays, as they often contain a liquid residue. This safely extinguishes the cigarette butt with a highly satisfactory hissing sound. For the inebriated smoker they combine the benefits of security and ease of use.
A strange substitute to be sure. This was introduced throughout fast food restaurants in the UK during the heady days of public smoking. As ashtrays they fell woefully short of any purpose, as the ash burned through them and left an ugly patina on the formica tabletops. They did prove to be popular with school children, who frequently lobbed them at other customers with astonishing accuracy.
Using a carpet as an ashtray adds a Bohemian look to a room. This looks particularly pleasing if the room in question is not your own.
Matchboxes are best avoided. A seemingly fine alternative to the ashtray at first, using an empty box, but after several problem free 'stubbings' a cigarrette is inadvertently disposed of in someone else's (full) matchbox, producing a dangerous firework display which usually ends in a teary visit to casualty.