COLOURLOCK Ink & Dye Blocker is a product to prevent the migration of ink and other dye stains coming through on a coloured area. This is very effective when repairing stains caused by marker pens, ballpoint pens, glue migration or black mildew. Such marks often migrate through the colour layer after a while. Applying the blocker will prevent this. Important: Clean the dye stains throughly to remove as much dye as possible before using the Blocker.