Mannitol (C6H14O6) is a soluble sugar-alcohol that chelates alkali metals and is commonly used to remove adsorbed boron from mineral surfaces before isotopic analysis. Boron (B) and lithium (Li) are both light incompatible elements that substitute in clay minerals; therefore, the potential for mannitol to extract surface adsorbed Li was studied. Lithium was adsorbed on <2 μm kaolinite (KGa-1) and smectite (SWy-1) clays, and on <20 μm quartz, from 1.0 M LiCl and LiOH solutions. Differences in surface attraction for Li+ result from the mineral point of zero charge (PZC) and solution pH. Various concentrations of mannitol (0.1 M, 0.5 M, 1.0 M) were tested for Li-extraction. Efficient Li-extraction requires mannitol concentrations approximating molar amounts of adsorbed Li. Mannitol molecules (>5 nm) cannot enter clay interlayers easily, but nonetheless extracted large amounts of soluble interlayer Li. Smectite adsorbed the most Li (2.2 wt.%) from LiOH, and >99% of it was removed using 0.5 M mannitol at 25°C in 24 h. Lithium bound in the interlayers can then be retrieved for isotopic analysis using NH4Cl cation exchange. This methodological framework for isolating different reservoirs of Li in clay provides a tool for tracking fluid δ7Li evolution during clay alteration. It opens new possibilities for evaluating fluid δ7Li evolution in asteroidal clays. Structural Li records fluid δ7Li at temperatures of neoformation, while interlayer-bound Li preserves the δ7Li of most recent fluids. Overall, this study demonstrates that mannitol is an efficient and environmentally benign alternative to harsh acid extractions for ore-grade Li adsorbed in clays.