The present invention concerns a method for treating waste material comprising: —Collecting release coated cellulose or polymeric sheets from producers and end-users thereof in the form of dense, bulky masses, such as rolls and stacks； —Pre-shredding the dense, bulky masses of release coated sheets into smaller, less dense masses in preparation to the following process steps； —Preparing the pre-shredded material by mixing, separating foreign bodies like metals, etc., and feeding it to a primary grinding station (3)； —Grinding the materials into small pieces, of the desired size, preferably down to less than 1 mm； —Adding additives selected from flame retardant, hydrophobic material, pesticide and mixtures thereof and mixing them with the recycled material； —Optionally forming a batt or a sheet by a wet process and/or by adding a binder.
