It is not commonly known that 'swan' as a verb is the past participle of 'swin'. Swin-swaan-swan. Swin is a an archaic term from Welsh farmers, meaning "to win in a sneaky manner". They coined it to taunt the English who attempted to buy their coal at reduced prices during rough times...often mixing black obsidian with the coal to reduce the amount of heat obtained and confuse the speculators.

Thus..."Let's swin this guy...12 pence a tonne...ha!"