Use copper mesh ,not potscrubbers,. The copper will give the proper reflux action and remove any nasties, giving you a good clean whiskey. The rascheling rings are a pain in the as,.,if you use them it will not be long before you start asking questions about stuff to filter the whiskey with.

Copper reacts with the sulfur in the steam. it removes it which improves the distillate but also corrodes the copper. After a couple of runs through you need to clean them.

An easy way to do this is to fix up a cleaning solution in a large flat tub, unravel your copper mesh plugs and just wisk them back and forth till clean. Since the copper goes from black to nice and shiny it is easy to see when you are getting the results you want. Rinse thoroughly , dry, and then you are ready to roll them up and use as plugs for the next batch. Note this use of copper as a catalyst as well as the reflux medium is only appropriate for ethanol solutions.

Rasching rings take a long time to heat up ,slower start up time, are far more likely to surge, and are harder to clean. They do work however.

What is the actual cleaning solution?

to get a better result, add some table salt to your mixture.