In several places in Australia tyres have been bundled together and sunk to the bottom of the sea to make artificial reefs. In a short time they are covered with marine life and attract schools of fish. Also old tyres are used in playgrounds for kids to swing and climb on with no ill effects. While they may not be suitable for potting mix let's not demonise them. Alan -- ----- No virus found in this message. Checked by AVG - http://www.avg.com/ Version: 2014.0.4765 / Virus Database: 4040/8362 - Release Date: 10/10/14