A police clearance or police check is an official government document stating a persons criminal record. If you don't have any disclosable convictions the document says as much. If the country you hope to be house sitting in is not the country you normally reside in you will need to obtain the police clearance from your country of residence.

Australian citizens: In Australia you can either call in at your local police station and fill out a form or search on line for the term "police check" or "police clearance" followed by your State. The form and copies of proof of identity, needs to be endorsed by a JP and sent off with payment to the relevant authority. The fee is around $50 depending on which state you are in.

UK citizens: In the UK this document is known as a "basic disclosure" check. UK residents can obtain one from ‘Disclosure Scotland’, which is a government agency and covers the whole of the UK. A fee of around £35 is required. http://www.disclosurescotland.co.uk/apply-online/

USA citizens: In the USA you can call in at your local police department, fill out a form and request they conduct a local or state criminal records search and provide you with a document reflecting that there is no history of a criminal record. They will let you know what else is required, such as fees and providing them with notarized proof of identity. More information can be found here: http://travel.state.gov/travel/tips/emergencies/emergencies_1201.html