It has sometimes been recommended to wash a precipitate with a ‹saturated› aqueous solution of the precipitate itself, in place of with pure water. It was reasoned that the solution, being already saturated with the salt, would not be able to dissolve any of the precipitate obtained. That is true; but if a saturated solution of a salt, MeX, is placed on a filter still holding an excess of the precipitant, ‹i.e.› one of the ions, say X, of the precipitate, then this excess may cause supersaturation of the saturated washing fluid and some of the salt may be precipitated out of the washing fluid. The method, as commonly employed, has therefore the inherent fault, theoretically at least, of being liable to give too high results. If it is to be employed without error, precautions must be taken first to remove, from the precipitate and filter, the mother liquor (containing the excess of precipitant) as completely as possible. If in a given case this can be accomplished, then the danger of precipitating any of the salt (MeX) from the saturated solution is avoided, and the precipitate (MeX ↓) may then be further washed with a saturated solution of the same salt (MeX), with advantage, in certain cases. Thus, in the Lindo-Gladding method[314] of determining potassium in the form of potassium chloroplatinate, the source of error, just discussed, has been avoided in the following way: the excess of precipitant, chloroplatinic acid H_{2}PtCl_{6}, which has the ion PtCl_{6}^{2−} in common with the precipitate, is ‹first removed› from the precipitate by thorough washing of the precipitate with alcohol; subsequently, other impurities, ‹e.g.› sulphates, soluble in water but not in alcohol, are washed out with an aqueous solution of ammonium chloride[315] that has been saturated with potassium chloroplatinate. The method gives good results.