A silicone rag is one of the most useful items to have in your range bag.
It has multiple applications for IPSC shooters:
First and foremost it can be used to improve the feeding reliability of your magazines. Many top US shooters run their bullets through the silicone rag before loading the ammo into the magazine.
When slightly coated with silicone, the bullets roll better in the magazines, and magazine feeding problems are eliminated. You can also run the silicone rag through your mag tube when cleaning.
Use the rag to wipe down the outside of your gun and magazines to prevent rust and remove finger marks.
The silicone rags come packed in individual zip bags which prevent the rag from drying out.