There is a lot of buildup of dirt on the case where it recesses into the port openings. Is it a problem and what is the best way of cleaning it?
use q-tips or compressed air to try and clean the ports
as for it being a problem there shouldn't be one as long as it doesn't mess with the connection
If the muck is really stuck on, you can use a small amount of alchohol on the Q-tips to help unstick it.
Q-Tips or dry cotton wool should clean your ports well.
As for the mag-safe charger port, the magnetism can hold some dirt to it. This can be hard to remove but Q-tips and a little extra effort should clear it out
A soft toothbrush can be used to loosen debris, then use a little compressed air to blow it out. If you are going to use alcohol, be sure to remove the battery first, to avoid shorting anything out.
I advise against alcohol, if it get's in the port- your port may end up permanently screwed. Ditto at the compressed air though.
Used a clean make up brush and that did the trick of removing any sand, dirt, lint from the charging port