Before paper was invented, scientists used dusty car surfaces to map complicated graphs, solve complicated theorems, and invent new swearwords. Protect your car from dirty dust and language with today's Groupon: for $6, you get two express exterior car washes at Joe's Seat Cover & Car Wash, with locations on North Seneca Street and North West Street (a $11.90 value).

Since 1954, family-owned Joe's Seat Cover & Car Wash has dutifully de-gunked the exteriors of cars with a thorough rub-and-scrub process, restoring sheen to four-wheeled friends. The express exterior car wash carefully caresses the frame's muddied façade with cleaning agents, restoring the body to glowing vibrancy and giving the car enough confidence to climb the social ramp toward VIP parking. In just a few minutes' time, cars shrug off their filthy road remnants and bask in a pampering bath, singing as soaps snuggle up against their exoskeletons and scrubs away signs of birds' aerial tic-tac-toe tournaments. Customers receive two washes to maintain their modern carriages' glistening, aerodynamic shell.