Reminds me of how a well known saying came into meaning:
Ships from Newcastle would bring their cargo into London’s docks, then rather return empty they would take a load of urine - which was used as dye for clothing - back with them.
On said return journey they would often pass other ships whose crews they knew, who would enquire what cargo they were carrying. They would often say “ we’ve got a great load, really lucrative” to which the response was:
“You’re taking the p155”.