Question about the anti-freeze soak method... can you just drop the whole engine in there, or do you need to disassemble it first?

I have a couple of 4 stroke engines that need cleaning. They aren't gummed up to the point of not turning over, they will turn, but there is thickish fuel (still liquid) in the carb area and lots of varnish on the outside of the engine/muffler. I would like them to look better and cleaner. I believe they will run as is, but wouldn't mind cleaning up a bit to hopefully make them run better.

I also have several old - OLD - os engines that sat in storage for the last 30 years that are completely gummed up.

I am hoping to take the lazy way out and just drop the whole engine in, but wanted to ask whether or not this would be wise...