Me too! But, my mother does not always go to my home. I think that my situation is better than you.
Anyway, I will put my mother at the first in my heart. If I were you, I will explain to her clearly. Don't be anger.
u should ask her to bath more often and ensure that her clothes are washed. My new experience with indonesian maid, I found them, at least mine the hygiene standards are poorer than bun bun. Before my bun bun takes bath twice a day, early in the morning before she works and late in the evening after she finishes work, no problem. My new indonesian maid does not have a habit to take bath and needs me to remind her from time to time. So I fixed her a self cleaning programme, bath twice a day, in the morning and in the evening. For underwear, wash them every night after finish bath and for other daily clothes, wash them twice a week, in evenings. Change her bedsheet at least once a week and wash hair every other day. Others like flush toilet everytime after use, wash hands regularly and after going to toilet .........any thing that you can thought of. After adhering to the schedule, it seems a lot better at least, I can stay close to her and no bad odour coming from her. If you have BB, you need to double check her self cleaning schedule. If she does not stay clean, how can she take good care of your bb.