Some cars & trucks have this hideous
brown paint job which has the color of baby shit; hence the phrase, "baby poop
brown". This paint job is so old that it is often somewhat faded and has a matte finish (vs. a glossy finish as is usual for automotive paint jobs).
A 1970 Ford Maverick that I had in 1986 sported this type of paint -- faded, matte finish, and colored baby poop
brown.
{From a website featuring fictious "death battles" between
TV commercial spokespeople, spokesanimals, and spokesthings}:
This
fight shall take place outdoors on the breakdown lane in the southbound lanes of the I-5 freeway. Available to the embattled contestants are a 1976 Volkswagen Bug with a flat tire (or, "tyre" if you prefer) sporting a "baby poop
brown" paint job and with the
keys still in the ignition, a tire iron, a spare tire in the trunk (which is in the front, rather than in the back as is usual), several
beer cans (one of them is full) in the roadside ditch, a half-used
pack of matches, and the usual assortment of plants & weeds (including the poisonous foxglove) that you might find in a temperate north-American climate.