Dependsd on how old the blocks are. Those printed earlier than about 10 yrs ago were printed with a hot wax method and the lines will likely not come out. The wash out printing only was available in the mid 90's. So my best guess is no they will not come out regardless of what you wash it with
The issue is not how they may be ironed or gone thru the dryer but the method of printing. If you saw no difference when they were washed then the blue marks are there to stay
Last edited by Holice; 04-28-2012 at 12:18 PM.