If you say "Beer-Can" it sounds like a Jamaican guy saying "Bacon"

At what point of the night do ashtrays disappear and tins of Tennents take their place?

It's a subtle and almost imperceptible process but it does happen, as I would gladly tell you as I pick the fag douts out of my sink on just about every Saturday and Sunday morning. It's with regularity that I am taken by surprise, having being decanting the amber nectar from its vessel into the sink on a post-party clean-up mission, a naked fag dout (having had his wee orange jacket soaked off) pops out the tin and into the plughole like a tabbaco stowaway on a cheap beer submarine.

In fact, it's not just beer tins that make this mysterious transformation; candles, bottle caps, glasses, other fag packets and some people even just tap the fag ash into their cradled hand.

What.the.fuck.

I think the equation for turning something from "just a thing on a table" to "ashtray" is like this:

laziness+(proximity of actual ashtray+need for nicotine)/creativity=

your girlfriends handbag is now an ashtray