The website surplusrifle.com has good information on MANY different rifles and pistols, including the SKS. Follow instructions on field stripping, and use the supplied cleaning rod and parts. If you do not have the original cleaning rod, you will need to get a cleaning rod, a .30 cal ore brush, and a patch holder. If you are shooting corrosive primed ammo (most older Soviet and Chinese ammo IS corrosive) then the bore and gas piston will need to be washed with hot soapy water.
No. PA does not require gun registration- and the SKS is not an assault rifle- it is a semi auto rifle with a fixed magazine.
The SKS is not an assault rifle, nor even a BATFE-defined "civilian assault weapon". And no, a permit is not required.
The SKS isn't an assault rifle, and the value may range from $100 to over $1000, depending on specifics.
Markings.
Assault rifle is a legal term, and laws vary place to place. Under MOST of them, it is a centerfire semi-auto rifle larger than 22 caliber, with a removeable magazine that holds more than 10 rounds, and a pistol grip. The SKS does not have a pistol grip, and has a fixed 10 round magazine. Not an assault rifle.
5000-10000 usd
About 400 meters
The SKS isn't an assault rifle, although some of the Chinese variations (such as the SKS-M and SKS-D) do meet the criteria for the definition of a "civilian assault weapon" by BATFE regulations. Although China was prohibited from further arms sales in the US in 1994, the Type 56 carbine (Chinese designation for the SKS) is still pretty widespread, and can still be found at gun shops, gun shows, pawn shops, online gun auction sites, etc.
All centrefire semi-auto firearms are classed as Category D under Australian law, and only occupational shooters may possess them. Collectors may own only deactivated rifles. And the SKS is not an assault rifle.
50-500 USD depending on specifics
Is it marked with Chinese characters or in the Cyrilic alphabet? <><><> As above. In addition, MOST Russian SKS rifles had blade style bayonets. MOST Chinese rifle had a spike type bayonet. But marlings are the defintive answer.
$125.00 to $225.00 condition and matching numbers on the parts has an effect on price .