The present disclosure provides methods and systems for in situ cleaning of hot gas flowpath components of a turbine engine that form portions of a hot gas flowpath extending through the turbine. The hot gas flowpath components may include a layer of accumulated contaminants on first portions thereof that form a respective portion of the hot gas flowpath. The first portions may include a thermal battier coating (TBC), and the layer of accumulated contaminants may overlie the TBC and at least partially infiltrate into the TBC. The accumulated contaminants may include CaO—MgO—Al2O3-SiO2 (CMAS) partial melt. The methods may include introducing an acid-including detergent into the hot gas flowpath of the turbine engine and onto the hot gas flowpath components to clean the accumulated contaminants from the first surfaces of the components.