After doing an initial clean on an office block, and waiting for months for payment, I went armed with yellow cardboard plackard and black felt tip pens.
If payment was not forthcoming, I intended to pop around to local radio station and ask them if they were interested in a story a bit better than a cat stuck up a tree. There's a man on top of an office block with plackards that say " this firm does not pay it's bill's"
I had parked my van right behind the managing directors car, so he could not move it.
They must have come to the conclusion I meant business, because I got a cheque there and then, without having to put felt tip to cardboard.