Most knit uppers do well with a dry cloth for loose dirt. Selected styles can be machine-washed on cold, inside a laundry bag, then air dried away from heaters and direct sun.
Do not put wool or tree-knit shoes in a dryer. For leather-alternative or canvas uppers, wipe with a damp cloth and let them dry on a shoe tree or stuffed with paper. When in doubt, follow the care note on the product page.