It seems that oil shale ash was even more effective than lime tuff and lake lime. On the basis of the investigations conducted by A. Khallik, the use of oil shale ash in acid soil was adopted. Today, only shale ash and clinker (cement) dust are employed in the Estonian SSR for liming acid soils. Of the total amount of employed lime fertilizers, more than 70% are made up by dust materials - dust oil shale ash and cement dust, although the use of the latter was only begun in 1964. The named waste products are ideally fine and are absolutely dry. This report covers its chemical composition and goes into field trials with different types of soils.