grease glands

Hello, I recently discovered the grease gland my piggy and was worried at first but started googling. I have cleaned it with coconut oil and got the gunky bits off but was wondering whether it is meant to be covered in hair... there is a lump but I can't seem to break up the hairs around it...

Can you really use this to clean piggies grease gland? I've seen it recommended on here, but surely that wouldn't be good for their skin..?

My boar has a build up of grease around his grease gland, I have tried to wash it off using coconut oil and guinea pig shampoo but he is a bit tricky to bathe, he hates it. Is there any way of making bathing more enjoyable or another way to clean his grease glands?