Possible Clues:

• University eight maybe that goes to pieces in the water?
• Person who washes may use one — but beach bum?
• Salts in solid form for use in the tub
• Tub water softener
• Water softener for the copper, pointless when child's about
• Water softener
• Soluble preparation getting black in each tub shifted
• Block of salts for tub
• Sailor turned to youngster among the relaxing salts
• Die for a dip - but beach is horrible