There are a lot of motor-powered items that use a chain, such as a snowmobile, motorcycle, or even some lawnmowers. These chains need to be regularly maintained like any other part on a vehicle, and occasionally, you may need to take the chain off to maintain other parts of the vehicle. The best way to do this is with a chain breaker, but not everyone has access to that tool. If you don't have one, then you can still separate the chain with a little bit of work.
Locate the section of the chain that you want to separate. Locate the rivets on the chain that you want to remove. Grind the heads off of the rivets using the rotary tool with the grinding disc.
Place the head of the flathead screwdriver between the middle of the chain and the top plate on the chain, just below where the rivets were in Step 1. Twist the handle of the screwdriver to pop off the cap on the chain, and separate the two sections of chain.
Repeat steps 1-2 for the exact opposite side of the chain that you removed in the previous steps. Pull the chain off of the various sprockets and away from the vehicle.