When you say the gun was not cleaned for a couple of years, do you mean that it was fired during that time, but not cleaned?
A muzzleloader that was fired a couple of times, and not cleaned for 2 years is one screwed up muzzleloader.
It may be too damaged to even mess with.
Might be a good reason why it is free, because it is worthless.
Pick up this bad boy for $109, one of the great classic inlines, the Knight Wolverine.
http://www.yeoldearcheryshoppe.com/knight-wolverine-p-7166.htmlThis is a $275 rifle, they quit making them a few years back, so this is a closeout sale.
Muzzleloaders are a pain in the ass to get shooting right. Centerfire rifle, you buy a box of shells. Every time you pull the trigger, it goes BANG. You don't need to clean it. Burn up 15 shells sighting in, and take the last 5 shells and go hunting.
With a muzzleloader, especially if you are new to the sport, you can easily spend $109 just getting the thing to go BANG and to get sighted in.
Do yourself a big favor and get a good rifle.