In the world today, harmful gases formed by fossil fuel combustion are a major burden on the Earth's ecosystem and atmosphere. Efforts of numerous scientists have been directed towards solving this problem. Biofuels are among the alternative solutions proposed, with biodiesel being the most widely used. It can be used independently or combined with diesel fuel in a classic diesel engine, either with minor or without any modification of the engine itself. Among its many benefits, the biodiesel is mostly known for being non-toxic, environmentally friendly, renewable, biodegradable and unlike traditional fossil fuels – it doesn't contain sulphur. Biodiesel can be produced from renewable resources such as fresh and waste vegetable oils and animal fats. However, waste oils and fats contain impurities, water and metals and they have to be purified to make a good raw material for biodiesel synthesis. In this work, the possibility of removing impurities, water and metals from waste fat has been investigated. Waste fat was refined with adsorption and extraction processes. Adsorption has been carried out using two adsorbens based on bentonite and extraction has been carried out using selected deep eutectic solvents and ionic liquids. The best process conditions for adsoption and most effective solvent for extraction of impurities, water and metals from waste fat were selected based on the obtained results.