Pajero Owners Club of South Africa

Maintenance: After driving for a while with seat covers on, re-adjust ladder locks.
Wipe marks/dirt off seat covers with a damp chamois.
Wash when necessary – cold water hand wash with mild soap solution.
N.B Ensure there is no bleach in the soapy solution
Do not aggressively scrub marks/stains. Rinse with cool water, line dry.
Just before dry, fit covers and leave vehicle in the sun with doors open. The cotton cover will shrink a little when they are washed, but will stretch back to full size when they are refitted.

Scubadude wrote:This is from the website of a Melville & Moon competitor, but suppose it will work for all canvas covers:

Maintenance: After driving for a while with seat covers on, re-adjust ladder locks.
Wipe marks/dirt off seat covers with a damp chamois.
Wash when necessary – cold water hand wash with mild soap solution.
N.B Ensure there is no bleach in the soapy solution
Do not aggressively scrub marks/stains. Rinse with cool water, line dry.
Just before dry, fit covers and leave vehicle in the sun with doors open. The cotton cover will shrink a little when they are washed, but will stretch back to full size when they are refitted.

So maybe just rinse them again and refit before they are completely dry ...