I am trying to remove the 6 gear sprocket on the rear wheel to remve, clean and lubricate wheel as it has not been used for some time. It has loose ball bearing and cannot be fitted with a ball race.

Robert O'Dalaigh, October 2011

If you want to lubricate the bearings in the wheel, you don't have to remove the sprocket cluster.
It takes a bit of practice, but remove the locknut on the axle, opposite side to the gears. Then undo the cone (it has very thin flats on it), this will expose the balls. Make sure you dont lose any and preferably count them before removing. You can then pull the axle out from the gear side, exposing that sides balls. Count if possible and remove them.
Clean the balls, cones and cups inside the hub. Look at the cones for damage. With grease on your finger, lay a healthy smear in the cup on the gear side. Lay the balls in the grease, then slide the axle in. Flip the wheel , making sure the axle doesnt come loose allowing the balls to fall out the other side. Smear grease in the non gear side, place the balls, screw in the cone till its just allowing the wheel to spin freely without play. The fit the locknut and tighten, making sure it all stays free. The axle can move and let things tighten up, you keep playing until its free but not too loose. It can takle a few goes.
You really need a cone spanner though, to fit the thin flats.

ColW, October 2011