The major contaminants in recycled paper mill, various sticky materials, have been a great concerns in paper recycling because the sticky materials have great adverse effects on the runnability, productivity, Product quality and so on. In this study, the quantitative method for evaluating the potential sticky materials in the recycled fiber stock was introduced. In a typical newsprints mill, the amount of the sticky material was traced depending on the processes, Especially, the froth flotation process showed great efficiency for removing various sticky materials and the optimized operating way of the froth flotation process was introduced.