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.

You could use Q-Tips, but I recommend another method.

You could buy this thing called a Giottos Rocket Blower. It's mostly used for cleaning dSLR's but it can also be used to clean laptops and etc. I actually own one and to tell you the truth, the air that it outputs is pretty strong. You can google it if you want to.

Now what you can do with the Rocket Blower (it's powered manual meaning that you have to squeeze the body of the Rocket Blower)is that you can use it to blow the air into the ports. I have tried this before and it removed about 90-95% of the time.

Hope this helps.

I advise against alcohol, if it get's in the port- your port may end up permanently screwed. Ditto at the compressed air though.