Hamburg - Vinyl and tonneau roof covers of convertibles need special care and should never be cleaned with pressure hoses that could damage the sensitive material.

Germany's technical testing authority warns that using a high-pressure hose from a close distance could even irreparably damage the vinyl.

Use a wet or damp cloth in plenty of soap and water to clean away the dirt. The cover should be wiped clean in gentle, circular strokes and the car rinsed to wash away all the soap.

Never use hard brushes to remove such stains as bird droppings as they could also cause bad scratch marks. Rather use chamois leather or microfibre towels.