Light rust on block

Just picked up a 340 block that I am told
was bored, new cam bearings ready to go
but then sat uncovered in a garage for
5 years and now has a light coat of surface
rust over entire block, cylinder bores and
lifter bores included. Looking for a cure.

take it to a machine shop and have it ran thru a parts washer. might get away with scotch brite and wd40 on the lifter bores and cylinders. if there is any pitting you may be in trouble and need to re hone the cylinders