We often get the questions about draining vintage motor oil cans or not, and if draining affects value.
Most collectors prefer to drain oil cans in their collection. Several issues are at stake.
* Old cans can leak, causing a mess, especially composite cans.
* When dropped or falling off a shelf, a full can's weight can cause more damage and possibly start leaking.
* A large collection of full cans could be an insurance problem if there was a fire or earthquake. Standard coverage may exempt a claim involving storage of a large amount of oil in cans.
* Shipping on an empty can has less cost and damage risk.
There are some collectors who will pay more for a full can, but they are in the minority. If the can has good graphics, appearance and condition, most collectors are not concerned about full/empty.
Collectors use several methods to empty cans. Most drill or punch two very small holes in the bottom of the can and let it drain. Some rinse the inside with solvent or detergent solution. Some put tiny dabs of clear silicone in the holes to ensure no future drips.
The drained oil should not be used in modern automotive engines since the older oils don't have the current service ratings for heat, close tolerances, etc. Motor oil retailers are often required to accept drain oil for recycling.