Here's how I dip my call barrels when I dip them in a finish.
I first start off with this style of paper clip. The medium size ones and large size work pretty good. You don't have to modify the clips in any way. Just squeeze them a little to get them unhooked from the base part of the clip.
When the call barrel is ready to be finished, insert the paper clip into the barrel and take the lid off of the finish you are dipping the call in.
Slowly lower the call into the finish. I try to lower mine fairly slowly into the finish and at an angle.
Once the call is submerged, I try to hold it in the finish for a couple minutes just to make sure that all of the air bubbles leave the surface of the call. You can wiggle the call a little to help the process, but don't stir up the finish too much and splash it all over the place.
Removing the call from the finish is the most critical part of the step. I pull my call barrels out at an angle. I also pull my barrels out of the finish at a rate of around an inch per minute. Pulling them out slowly and at an angle will allow the finish to get an even coat. Pulling it out too fast will result in areas that have a thicker finish and more drips.
Remember to go slowly. You will want to see what it looks like, but have patience.
Hold the call for a little bit to allow most of the drips to drip off.
Hang the call up to dry. I hang the call at an angle. It allows the drips to collect in one part of the call.
Set a timer for 30 minutes.
When the timer goes off after 30 minutes, touch a rag to the drip to remove the drip from the call.
That's how I do it.