Petrol and diesel drivers have been urged to "steer clear" of car washes that have these major red flags, with motorists at risk of picking up serious damage. Experts at Ovoko have stressed individuals should dodge car washes where individuals can see dirty water in buckets.

Meanwhile, grimy-looking cloths and tattered foam brushes could indicate a serious issue, with vehicle bodywork possibly at risk. If motorists spot these problems, they should consider walking away or washing their vehicle at home. This will ensure motorists always use clean products that are unlikely to leave marks longer term. Kazmieras Urbonas, Supplier Excellence Manager at Ovoko said: "If the facility looks generally unkempt, chances are their cleaning standards extend to their equipment maintenance as well."

Specialists have warned the damage caused by dirty car wash equipment doesn't always show up immediately.

However, small pieces of grit and dirt may be left over and rubbed into bodywork, leading to micro scratches.

This can lead to costly repairs with total bills likely to depend on the extent of the damage and type of vehicle drivers have the keys to.

Light surface scratch repairs could set road users back up to £110, with deep scratches costing up to £330 to fix.

Kazmieras added: "It's common for facilities to reuse the same cloths, mitts, and foam brushes throughout the day without proper cleaning, allowing grit and debris from previous cars to accumulate.

"What many people don't realise is that those seemingly harmless brushes and cloths can become loaded with sand, road salt, and microscopic particles from dozens of other vehicles.

"When these contaminated materials are dragged across your paintwork, they act like fine-grade sandpaper."

Ovoko stressed that touchless car wash machines may offer slightly more protection for road users.

These simply rely on high-pressure water and soap, meaning there is next to no risk that brushes could become contaminated.

However, they have stressed these machines are unlikely to achieve the same level of deep cleaning as hand wash services.

Mr Urbonas explained: "A good car wash will be transparent about their cleaning process.

"Don't hesitate to ask how they maintain their equipment - reputable businesses will be happy to explain their procedures."