Can you give me some idea of the sizing for small and medium sizes. I would like to purchase black leggings. Also, best to wash by hand? Thank you.

Thank you for asking. We added the chart with dimensions of this garment as stated by the manufacturer. https://naturalclothingcompany.com/products/organicleggingscapri
Because of stretch it's bit hard to measure these exactly but in our experience, these leggings run bit on a smaller side. 

Care Instructions state:
Machine wash cold, gentle cycle. Line dry. Use mild detergent.
Of course, the hand wash is always the gentlest on the garment.