Have the usual issue this time of the year of getting to the boat and finding loads of dead flies on the seats & hatch upholstery.
The boat is under a boat shed roof so no covers over the boat (like it to dry out). ... covers don’t go on until close down for the season.
Some of the flies leave a black or orange stain ...... I use a marine multi-surface cleaner, it removes most stains, except the red dots.
Anybody have a good vinyl cleaner to recommend, don’t want to risk strong solvents as they may discolour or remove the plasticisers, and cause long term problems.