I spent approx. 4 hours polishing each spoke and nipple individually when I had my SE. The previous owner had fitted cast wheels, so I was able to work on each wheel without a tire fitted.
The spoked wheels reportedly had a slight leak, hence why they were changed and left in the shed for several years!
After polishing, I sealed each nipple from the inside of the rim with an adhesive, smoothed it over before it cured, then laid a band of 3M sealing tape around the rim.
This was back in July, and the wheels are holding pressure no problem.