Sick male

Question
I have 3 males and they all get this black stuff on there behinds above there genitals(where a tail would be).  My aunt told me that it is a gland or something.  What is that stuff and what can I use to get it off?  I bathe them about every other month or sometimes a little longer and I can't seem to get it off.  My other question is one of them has a little lump or something on his neck.  He has had it ever since I got him over a year ago and now it seems to be getting bigger.  He also has some sort of growth coming from his rearend where the "black stuff" is, sort of to the left.  They don't seem to hurt him, but he does whine sometimes.  I know they get plenty of Vit C because they are spoiled and get fed carrots, celery, cucumber, Tim hay, and their staple food everyday (veggies twice) and I occationally put drops in their water.  Should I go to the vet about these growth things or is there anything the vet can do about it?  I would not be able to stand it if Maddox died.  He is my first little man since I was a child over 14 years ago and he got me through a really bad time in my life about a year and a half ago!
Thanks, Laura  

Answer
Hi,
the black stuff is from a gland, I can't remember what its called though. To get it away put some dish-detergent on the rear of the pig and leave it for an hour or so. Then gently scrub at the area with a soft toothbrush, and rinse. Some pigs seem to have more of this stuff than others, and it can be quite hard to get away sometimes. One thing to think of is that the skin gets dry after a cleaning, so you have to keep an eye out for that.

I have no idea what the lumps could be. Taking him to a vet seems like a good idea though. I hope he is ok...