A seller of goods will often wish to retain ownership of goods until the money for those goods (or even all money owed to him by the buyer) has been paid. In addition he may seek to recover possession of the goods if the buyer becomes insolvent or the goods appear to be otherwise imperilled. If the goods are in their original form, enforcement is relatively easy. However if the goods have been processed or sold, then claiming ownership of mixed goods or the proceeds of sales can be legally problematic.
Easyform Glossary of Law Terms. — UK law terms.