For situations where the rings have stuck to the cylinders from humidity..and/or the red fuzz has grown in the cylinders..i have used with great sucess in the past a product called "safest rust remover" take the plugs out..fill up the cylinders..put the plugs back in..wait 24 hours..remove plugs..drain the product from the oilpan..rotate the engine to the tight spot..back it up a hair..refill the cylinders and replace plugs..come back in 24 hours..drain, remove plugs..check for rotation..dont turn the engine with the product in the pan to avoid drawing it into the oil pump and bearings.
New plugs,oil and filter..it should work fine..has for me..
Been sitting in a field with the head off for a decade, full of water..probably not so much..decarbonizes nicely too.
Not working for them selling their stuff or any of that..but it has worked really well for me..