The address you can send them to is Freepost LUSH GREENHUB. Please ensure all bottle tops are packaged well in either a cardboard box or envelope.
Bottle tops are melted down, pressed into board and made into useful things from wall cladding to furniture and beehives. For example they've even been used to make a play area at a refugee camp in France.
For further queries please feel free to contact LUSH customer care number 01202 668545 or email them at wecare@lush.co.uk