If you haven't already I'd try dry brushing it first and maybe a gentle hoover to remove as much mud,dust as you can. It might take a few passes though
I'd also be tempted to contact FMB to get some advice so you don't affect the adhesion of the base tape
If you haven't already I'd try dry brushing it first and maybe a gentle hoover to remove as much mud,dust as you can. It might take a few passes though
I'd also be tempted to contact FMB to get some advice so you don't affect the adhesion of the base tape