Is there anything i can use to reduce the musky smell of my ferrets as they live indoors. EG oil or powder?

No; you can try cornstarch. DO NOT BATH. The more you bathe a ferret the more they will smell. Their oils go into hyper active drive to make more, which in turn causes them to smell more. Wash their bedding 2 times a week. Clean litter boxes everyday. The musky smell is natural of ferrets. It is their bedding and cloth items that hold the smell. They do have something similar to a spray for ferrets, but never used it.Is there anything i can use to reduce the musky smell of my ferrets as they live indoors. EG oil or powder?
Keep their cage/hutch very clean, spay/neuter them and bath them once a week. Other than that, white wine vinegar and lemon juice are great for neutralising odours and won't harm your ferrets :-)Is there anything i can use to reduce the musky smell of my ferrets as they live indoors. EG oil or powder?
If they are hobs (male) castration does help to reduce the smell somewhat. I used to bath my ferrets once a week with a mild baby shampoo. Keep their sleeping quarters/cage very clean.
Keep them down your trousers with plenty of talcum powder to reduce both smells!
stick them outside where they belong