A tricky one to replace effectively rubbish free, however its usefulness is declining as computer based word processing increases I suppose.
The best product we've seen so far is from Office Products Depot and is a correction tape made from 67% recycled material. It is called 'Liquid Paper Dryline Grip Recycled Correction Tape' with the product code: 7519751
We'd love to hear of any alternatives, so please email if you've got a suggestion. Thanks!