How do I clean the Poly Carbonate Holes?
We have our car shed roof made from double walled polycarbonate sheets, the problem is that the fabricator at the time of fixing it to the frame forgot to put tape on the holes to avoid dirt getting in. and that time I didn't knew about it, but recently I read this and the dirt has seeped in the holes which are about 7mm square in area. I googled it with various queries but to no avail, Now please help me by giving me some direction and steps to clean it.
The dirt is fine sand and some mud which seeped in with rain.
I do not want to cut replace or open the sheets just clean them.
it has seeped in upto 1.5 feet (roughly half a meter).
See the following images, the dirt is just dark areas the rest is just on surface.