Black bugs are usually mites. You need to soak the beardy and use cotton buds to get them off (focusing on the eyes, armpits and folds of the beard). You can get mite-off or I hear a diluted betadine bath is also good for getting rid of mites.
As well as bathing you need to tackle the enclosure otherwise they'll keep coming back. They hide on decor, substrate and any nooks and crannies in the tank. You can soak all of this in a betadine bath too or a diluted bleach solution. You may have to do this a number of times before you're all clear of them - in this time it's best to use a disposable substrate such as newspaper or kitchen roll