If the rental car is dirty, request cleaning or another car directly from the rental company. If the rental company is unable to clean the car promptly, you can have the car cleaned yourself. In this case, make sure you get an invoice.

You can use this invoice to file a claim to get the money for the cleaning refunded after you return the rental car. Photos of the dirty car are also beneficial.

However, a reduction in the rental price is only possible in the case of considerable soiling (e.g. smoke, vomit) and is at the discretion of the rental company. Crumbs on the seats, for example, are unfortunately insufficient grounds.