Possible Clues:

• Tell all to turn up fresh
• Tell all
• Reveal dirty secrets
• Admit those who have washed before arrival
• Truth to tell, you should have a bath before you arrive
• Be honest, you'll have wash before you arrive
• Informally, confess fully - arrive washed?
• Do without anagram of lace, following compiler's own
• Admit it, you've got to wash before you get there
• Do your washing before you arrive, and be honest about it