Optimising the flotation cleaning stage is a critical component in achieving high-grade concentrates without compromising recovery. The cleaning circuit acts as the final refining step in the flotation process, where selective rejection of gangue and upgrading of valuable minerals occur. However, the cleaning stage is often overlooked compared with rougher performance, despite its pivotal role in overall plant efficiency and final products quality. Effective optimisation requires a detailed understanding of mineralogy, flotation chemistry, and circuit configuration. Key strategies include adjusting grind size to liberate locked minerals, optimising reagent regimes, extending flotation times, and modifying circuit layout. Regrinding rougher concentrates to finer sizes can improve liberation and selectivity, while targeted reagent additions such as collectors, depressants, and frothers, can enhance separation. Recirculating scavenger material to the cleaning circuit, adding dilution water, increasing residence time and wash water control are also effective approaches. Each of these strategies aims to balance concentrate grade improvement with minimal recovery loss. In practice, however, cleaning stage optimisation is not a one-size-fits-all solution but a process of continual learning and adaptation. Achieving optimal performance is challenging as each ore type has distinct mineralogical characteristics, surface oxidation states, and mineral associations, meaning that circuit changes effective for one deposit may underperform in another. Additionally, electrochemical factors such as galvanic interactions between sulfide minerals, the presence of ultrafine particles, and slime coating on valuable mineral surfaces can significantly affect selectivity and concentrate quality. Managing these effects through controlled regrind conditions, targeted dispersants, and optimised pH and redox potential is crucial for successful cleaner performance. This paper presents a series of case studies highlighting cleaning stage optimisation in complex base-metal and polymetallic systems. Examples include regrind and cleaner-scavenger circuit implementation in copper ores, selective depressant strategies to improve lead and zinc separation, and reagent modifications that enhanced gold and silver recovery in sulfide circuits. The findings highlight the importance of integrating mineralogical characterisation with laboratory flotation test work to guide circuit design and optimisations.