I dont soak, just hold the bird for a few minuets after applying the iodine. The soaking is probably helpful but you could probably do it every other day and still get good results. Once a day application of antiseptic is fine. The beauty of the no bandage method is you can treat as your...
Just hold the birds feet out for 3 to 5 minuets while the antiseptic works, then let it free. Repeat daily if you can but i usually do every other day for a week and after that its on the mend. Its worth noting that really bad bumble with a huge scab that covers the entire heel type of thing...
I gave up on bandages right quick! This was the process recommended to me by a vet. Just use antiseptic worked in with an old tooth brush. Hold the bird for 5 minuets to let it work then let it go. It works so well i was surprised. If you have 1 duck with bumble wrap feet to your hearts...