Royal Berkshire Fire and Rescue Service (RBFRS) are holding a series of car washes throughout September for The Fire Fighters Charity.
More than £12,000 was raised by the fire service in March at their previous car wash marathon.
Watch manager Sarah Lewis, charity co-ordinator, said: "The Fire Fighters Charity does such important work supporting serving and retired firefighters, fire personnel and their families when they are in need.
"It is entirely reliant on the generosity and enthusiasm of its supporters."
The car wash at Maidenhead Fire Station, in Bridge Road, and Slough Fire Station, in Tuns Lane, will take place on Saturday, September 27.
The suggested donation is £5 per car.
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