Someone once said no ................. effected me for months
knock knock
Hi do you need a window cleaner ?
or
Hi Im the local window cleaner looking for a few more customers do you need a window cleaner ?
or
Hi do you have anyone looking after your window cleaning at the moment ?
or
Hi whatever your window cleaner is charging I will do it for £2 less
the last one was a joke btw
easy peasy simples
never say summit like "oh er hmmmm hi sorry to disturb you but do you ...."