This Bureau of Mines report describes the washability characteristics of 13 coalbed samples collected in Colorado. Such data are needed to evaluate the quality of the coals of the west, where most of our low-sulfur-content coal reserves are found. Of the 13 samples included in this report, 11 had a total sulfur content of 1 percent or less. All of the samples contained low percentages of ash or could be readily washed to a desirable ash level with minimal loss of yield. The coals ranged in rank from high-volatile a bituminous to subbituminous b; nine of the samples were high-volatile c bituminous. The coalbeds ranged in thickness from 6 to 26 feet; the average was about 8 feet.