Fine guns deserve fine treatment. At the end of every season you should submit your gun for a service, or strip and clean as it is known in the gun trade, to a time-served gunsmith.

From “Shotgun Technicana” - McIntosh & Trevallion

The gun will be disassembled into its three parts: Lock, Stock and Barrel. Each will be stripped down and examined for wear or damage. The gunsmith can then assess the gun’s condition, report any malfunctions, agree a price for the work and carry out the necessary repairs.
Some of the more common faults and their cures are as follows:
The Lock is the heart of the gun where by spring, rod and tumbler the gun can, on opening, eject spent cartridges, along with cocking the hammers, ready for the subsequent shot.
These parts are finely regulated and require great skill to take apart. Once the lock is apart and inspected, any parts requiring repair or replacement are identified and the owner is advised before the remedial work is carried out. The parts are re-built and lubricated with a mixture of Vaseline and oil.
The action housing the lock is boiled in a special solution to remove dried oil and dirt, resulting in a clean, bright