I have to say that the term "dirty" is not the best one - I'm not a native speaker, my English is not the best...
A small part (less than 1mm) of an electronic component was between the board and the cpu - very, very seldom - i guess that's why all people in computer manufacturing factories wear strange caps.... Finally I have to repeat, that the G-70 is a real good keyboard and I'm a Roland Fan since 1987. The VA-76 was the first Top Keyboard from Roland, which didn't satisfy me - but with the new G-70 they are on the right path again.