if liquid, soak it up with rags or kitty litter and then dispose of it properly.
scrape up with putty knives any solids.
engine degreaser and power washer might help, but things will go everywhere.
it is better to keep it from flying everywhere

Wonder if this might work? Gunk engine degreaser. I use to degrease engines. Spray on, let it sit and hose off. Water soluble apparently.

That's ^^^ very similar to what I used, an engine degreaser followed by simple green. Muscle with a scrub brush did the job. Thanks all for the suggestions.

Great opportunity to consider an upgrade

Here's just some food for thought. I also suggest consulting Rodbolt17.

I paid a marina more money than I spend on fuel to diagnose and then rebuild my carbs after doing same myself and then realized I undid my work with the next key turn due to crap in the fuel system.

While Yamaha rates my carbed 2-stroke for 10% ethanol, it and the rest of the system isn't rated for the higher ethanol concentrations that occur as a consequence of phase separation.

I also realized my boating habits never use more than 1/3 tank, which meant I was always using old fuel. So years ago I ditched the 27 gallon white translucent console tank for a 12 gallon red topside tank, replaced all the fuel line and components from tank to outboard, use cheaper 3/8" soft annealed copper with flair to barp connectors except for short lengths at the tank & outboard. I also rigged a $26 12V solenoid fuel pump with hose and plug. The rig pumps all remaining fuel from the boat into the truck after every trip. I empty the carb bulbs and leave the tank open and upside down. Replacing fuel hose every other year now takes ten minutes.

The entire job took half the time as cleaning, cost only twice cleaning and much less than a failed trip. For me, this works. No fuel means none to go bad. To be honest, after returning on fumes, I added a separate six gallon tank. This past year we were out only twice. Both trips the outboard ran like an angry swarm of hornets and I expect the same next week.

The last trip I replaced the overdue 10 micron fuel filter and swore it ran faster. I'm thinking the old filter's added pressure loss starved the engine at WOT and maybe a 30 micron filter is more appropriate for a carbureted motor.

Shopping for an hour here, Amazon and marine retailers can get everything to your front door by the weekend and the swap can be done in faster than a schelp to the marina.