A useful distinction
A household may have a familiar washing routine, but garments can differ in fibre, construction and finishes. A routine that worked for one item is not proof that it suits another. Visible colour and texture cannot supply missing care instructions.
Put it into practice
Separate garments according to their actual care guidance and keep uncertain items identified. Note a past result without presenting it as a guaranteed method. Use qualified advice for an item whose information is missing rather than experimenting with irreversible treatments based on a generic article.