Shop|Historic Construction Materials|Clinker Coal Ash Clinker Coal Ash From£13.50 + VAT Clinker Coal Ash From£13.50 + VAT Clinker Coal Ash 25kg Coarse Grind Product NameQuantityPrice Coarse 2.5mm - 1.4mm £13.50 Clinker Coal Ash 25kg Coarse Grind Clinker Coal Ash used to darken lime mortars, Available in 25kg bags in a coarse grind.