Been using these type (Phone China marker) to mark on steel and some other surfaces. But these aren't ideal (not sure if they're just not well made any more or what), but difficult to sharpen and
Diamond China Marker Box grease pencils leaves opaque markings without skipping on all types glazed pottery, glass, plastic metal, rubber as
Sharpie Peel-Off China Markers
Cabilock 12PCS Peel- off Wax Pens Peel- Off China Markers Grease
China markers / grease pencils
Mechanical, Refillable Marking Pencil that writes on any non-porous surfaces, such as metal, acetate, plastic, glass, and even photos. Red grease pencils are best for marking on transparent and light colored surfaces. Wax lead is non hazardous and non-toxic making it safe to use in both industrial and households. Unlike peel-off china markers, these mechanical pencils can be used fully (no wastage) and can write on wet and damp surfaces.
Listo 1620 - Box of 12 - Black Color - China Markers/Grease Pencils/China Marking/Pencils/Wax Pencils
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Sharpie Peel-Off China Markers
China Markers, Grease Pencils, White China Markers in Stock - ULINE
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Color Peel-Off China Markers Grease Pencils Set Colored Drawing
12 Pack Peel-Off China Markers Grease Pencils for All Surfaces Art