I would guess that Seafoam will not mix with methanol. I do not know this for a fact but, IIRC, Seafoam is a "petroleum" base and therefor is not miscible with methanol.
I often put my finger over the end of the muffler when running full throttle to force fuel through the venturi. This flushes out some of the old oil that may have formed from storage. I normally dribble fuel over the front bearing too, and make sure the motor flops back and forth very well before I start it. I have a lot of planes that I don't fly often. Nitro is a very good solvent that mixes with methanol and the oils we use. Probably better than most snake oils.I myself pull the engines, most of the time. There have been times that I feel it won't take much to get it going on the aircraft. Some of the time I am right but have been times where I was just wasting my time as I end up pulling it anyway.
I didn't find the right solution from the internet.
References:https://www.groups.coforums/showthre.php?2993900eafoam-in-tro-fuel-Is-it-possibleBusiness Whiteboard Animation Video