I see this issue was raised in 2010 and again in 2015 but here we are in 2019 and every sheet of tekta I have is covered in these rust spots which are virtually impossible to remove. Most of the time I get around the problem by capping the tekta with a colour, however, this time I need to cap white opal with tekta and obviously this is a huge issue for me when all of my tekta has these rust spots.
Can you tell me what if anything is being done to resolve this problem?
Sue
UK