C.R. LAURENCE TUM8 CRL Medium Bronze Touch-Up Marker. CRL Touch-Up Markers will cover scratches on metal beautifully, and can be a real time saver to the glazier. They replace paint brushes or standard black felt tip markers better because they are an actual high gloss paint. Use them for thin scratches, to touch up cut ends of extrusions, or for covering screw heads. Vary the hand pressure of the point and you can adjust the width of the stroke. Positive-seal cap prevents the marker from drying out. Color coding on cap makes for easy identification.. Part Numbers Variations: TUM8