Methods for removing a residue of one or more biological materials deposited on the walls of a microfluidic conduit in microscale devices are provided. In an example of the methods, one or more colloidal-size particles, such as colloidal silica particles, are flowed in a fluid within the microfluidic conduit having residues of materials previously deposited on the walls thereof to adsorb to the materials and to remove such deposits from the walls of the microfluidic conduit.