If you have any diabetic friends grab a couple of needles off them and then start flicking the dirt off... Or if you have any welder friends get a couple of short lengths ( 4 inches is fine
) of stainless Tig welding rods... Grind one end to a sharp
point and the other to a sharp
chisle blade... I find these to be the best tools
With a steady hand and a glass
of decent scotch whiskey, pick
at the dirt, only with upwards motions...be gentle, both with the picking and with the scotch!
A binocular microscope is ideal, but hardly easy on a budget
... But illuminated magnifying glasses with a 4" lens are cheap
and wide enough to give you stereo vision...