1. A method of managing a set of values in a multithreaded computation in a system that performs value recycling, the method comprising: without using locks: indicating an intention to use a particular one of the values; and as a condition precedent to a particular use of the particular value: determining whether the indication alone was sufficient to prevent recycling of the particular value; and using the value for the particular use only if it is determined that the indication alone was sufficient to prevent recycling of the particular value.