Under optimal conditions (stored in the original, unopened containers at moderate temperatures), engine oil usually remains stable for an extended period of time. There should not be deposits on the bottom of the container. You cannot redissolve the deposits by simply shaking the container. The oil has to be replaced.
That said, an engine oil’s properties are best if it is used within two years. After that, we recommend changing the oil.
Don’t put the old oil in the trash. Oil should be recycled.