You can soak her in a dish pan, small sink (as in the bathroom) or a large bucket. A bathtub would allow you to really look at her wounds. This will require at least a bath daily until the wound is free of pus and maggots, and starts to heal. Use warm water and plain table salt added will be fine. The strength of normal saline which is what our tissues are made up of is 1 tsp per quart of water. I don't think you have to be so exact. A little betadine or hibiclens (chlorhexidene) in the water, instead, would be good. It doesn't matter what you clean with, even dish washing liquid in the water, but get the maggots out. Then use some plain antibiotic ointment or the SWAT. If you have a turkey baster, those work well to flush out wounds. A sink spray will do this too, used gently. Pictures can really help.