THE WINDOW CLEANER

A young woman starts work in a pharmacy. She likes the job but is shy about having to sell condoms and always leaves that to the owner.
But the owner, who’s going on holiday, wants her to run the shop on her own. So she confides her anxiety to him. 
‘Look,’ he reassures her, ‘my regular customers don’t even ask for condoms. Instead they ask for a 310 (small), a 320 (medium), or a 330 (large).’
The first day the woman is alone goes well. But on the second day a big guy comes into the shop, puts out his hand and says: ‘350.’
The girl panics and phones the owner on his mobile.
‘Go back in and check if he has a yellow bucket between his legs,’ her boss tells her.
She peeps through the door and sees he does indeed have a yellow bucket between his legs. 
‘Yes,’ she says, ‘he has.’
‘Then go back in and give him £3.50,’ the boss advises. ‘He’s the window cleaner.’