Not sure whoever serviced these wheels but it needs a rebuild with other hub cones.
You can see how bad the bearings are battered and this is in lesser degree also on the (in picture loose) hub cone.
Looking for a replacement to get these on the road again.
For bearing balls I use my local trading estate bearing factor for loose balls in the best grade available (typically 10 Grade) - I bought 100 or so a few years ago and am still working my way through them. He also sells online: