Most go straight into the bin. But we couldn't resist drawing your attention to this year's de rigueur fashion accessory.
A roll on the drums, please, maestro. For here comes the PWP Go Bag, the last word in disposable urinals and a contraption that gives a whole new meaning to taking the piss.
Caught short on the Croisette this year with a bladder full of rose?
No problem. Just reach for the Go Bag. According to its manufacturer, this cunning device instantly turns urine into an odourless gel, making the bag safe for disposal in a normal bin.
It's all down to the polymer crystals, which solidify the urine. You'll also be reassured to know that Go Bags are ergonomically designed for use standing or sitting.
Personal Waste Products, which makes the Go Bag, is bursting to offer us pictures and an interview with its marketing director, Carl Rees. We'll pass on this one, if you don't mind.