# all our righteous deeds are like a menstrual rag

A "menstrual rag" is a cloth that a woman uses during the time of month when she bleeds from her womb. This means all their attempts to please God fail. This sentence was meant to be shocking.

# We have all withered like leaves

Isaiah compares the people of Israel to leaves that dry up when dead. 

# our iniquities, like the wind, carry us away

This means their sins, as a community, are the reason for their failure. Isaiah compares the iniquities to the wind as the force for their suffering Yahweh's punishment.