A benchtop scouring procedure was used to evaluate the ability of conventional detergent scouring systems to adequately clean fleece samples from a selection of Western Australian Merino wools. Sixteen fleeces were selected from the Western Australian Department of Agriculture resource flocks, covering a wide range in yield (49.2 to 77.5%), wax (7.3 to 26.9%), suint (4.9 to 11.6%), and dust (1.4 to 16.3%) contents. Using a simple detergent-based system, 50% of the fleeces were classified as effectively scoured, based on residual wax content. When scouring liquor was not refreshed between subsamples drawn from the same fleece, wool wax, staple length and dust content in the greasy fleece accounted for 93% of the variation in the rate of residual wax increase observed in sequential 10 g samples of wool. Residual ash content also increased but the greasy fleece parameters measured were not statistically significant predictors of residual ash changes. The rate of scoured wool colour change, when sequential samples of greasy wool from the same fleece were scoured without liquor change, could be predicted from greasy fleece yields. The scouring efficiency of the more difficult to scour wools was improved by the addition of sodium carbonate to the main scouring bowls.