Governments worldwide are increasingly adopting behavioural science methodologies to address "sludge" – the unjustified frictions impeding people' access to government services and exacerbating psychological burdens. Sludge audits, grounded in behavioural science, provide a structured approach for identifying, quantifying, and preventing sludge in public services and government processes. This document delineates Good Practice Principles, derived from ten case studies conducted during the International Sludge Academy, aimed at promoting the integration of sludge audit methodologies into public governance and service design. By enhancing government efficiency and bolstering public trust in government, these principles contribute to the broader agenda on administrative simplification, digital services, and public sector innovation.