A method and laboratory system for handling sample tube racks are disclosed. The laboratory system includes a storage section (14) with a plurality of shelves (110) for storing a plurality of storage racks (SR), a disposal unit (18) for disposing sample tubes from the storage racks (SR), a robotic transfer system (510) for loading storage racks (SR) into the storage section (14), for retrieving storage racks (SR) from the storing section (14) and for bringing storage rack to the disposal unit (18) after a given storage time has elapsed.