Around $500
Start by getting the owner's manual for your rifle. You can get one on-line from Ruger Customer Service. You will need a basically cleaning kit- a .22 caliber cleaning rod, brush, patch holder, cleaning patches, powder solvent, lubricant. Then read the owner's manual, and follow the instructions.
Oil, bore cleaner, patches, cleaning rod.
Go to http://www.marlinfirearms.com/ and request an owners manual for the marlin glenfield model 60. They have changed little since 1980.
Ask a gunsmith for help
You must contact Ruger to avoid voiding the warranty for a correct answer.
Do you not have an owner's manual? Have you tried an internet search on "rifle cleaning procedures"?
yes, although feeding difficulties with 5.56 ammunition aren't uncommon with the Mini 14 Ranch.
Cleaning kits for rifles are typically purchased individually from the Post Exchange. Cleaning kits for heavier weapons are part of the unit's MTOE. Each rifle comes with a cleaning kit when it is purchased, but they typically get lost between the time the rifle is first issued to when it passes through many hands, thus facilitating the need for soldiers to purchase cleaning kits.
Pull it through the barrel
cleaning kit
listing the model and serial number would help a great for someone to estimate the value.................................and overall condition............................