Less obvious since I found out that my city's council taxes those cards. When the rain turns the usual dozen of flyers into a plaster that harden later with the sun, it takes a few minutes to clean at best.

File a police report for vandalism by the company?

Vandalism? So illegal activities are now taxed instead of fined? Not that I find more logical that the council rents my car to those companies as an advertisement medium. But there's zero chance that report would be taken seriously.

I understood your previous comment that you're already in a situation where it's taxed; I was thinking of someway to have it cost the advertising company money even if it only serves to have them put out the flyers on sunny days.

I was thinking more as tool for insurance and/or attempting to force the company to pay for the cost of an exterior detailing of your car since they plastered something to it (with the help of the weather).

In many US areas there are online police reports for minor incidents and the purpose of the report is almost solely so that you have a record for insurance.

It may also help if you call up the company (or publicly shame them with a tweet) to ask for reimbursement for the cost of a car detailer to remove their litter from your car without damage. Having a police report means you could put it all in the hands of your insurance company who have lawyers on staff or use it as part of the negotiation with the company.

Maybe enough police reports about a given company and you could petition the council to revoke that company's ability to flyer any longer?

I know I'm probably dreaming that it would make a difference. The only time I've had an experience with this a friend used twitter and got a public apology from the company along with some monetary compensation around the removal of the ink residue from the windshield.

It seems there's a huge culture difference here. Not trying to criticize the US way, I guess it works for you, congrats! Here I would be laughed at, unfortunately.

People that put the flyers on the windshields are just a step from insolvency, so no use to go against them. The "company" behind them, just a little step up the food chain.