What is the best way to clean the black exhaust residue from the back of my transom?

I am having the same issue. I tried simple green,and a couple of other things like that. The best thing I found so far is some wax. Squirt it on rub it in and wipe it of and boom, it's gone and my transom is shinny. Two birds with one stone.

Now I need to dial in my package.

starbrite hull cleaner

If it's gelcoat, some cleaner wax usually works well or Liquid Glass. If that doesn't work a light cut/polishing compound. If you have a white rub rail it works on that also.

Sno Bowl or Zep toilet bowl cleaner. Spray on, rinse off make sure to wax.

Acetone, that is if it is gel coat. Been using it for 4 years with no problems

I also find 3M bildge cleaner to work excellent.
Ken

I do the Simple Green stuff. Tends to desolve peroleum products and residue.

The wife suggested on using a spray called "Dawn Power Dissolver",in a blue bottle. It works great!! She also showed me how to use a sponge (not the contraceptive type) made by Mr. Clean called " Magic Eraser". It works really great as well. When we put the boat up on the hoist, she sprays the cleaner on and wipes down the swim platform while the spray does its trick. It sits for about 3-5 minutes and then she goes to town wiping it off. If she runs into a tough spot she then reaches for her sponge. I have had a lot of people look at my transom and comment on how clean it is for a boat with one of them Blue 525's in it and not spendng alot of time on it.

We use that sponge on all kind of things. You know that black stuff you get in some tight areas of seating and the hull, well it is no match with the sponge. I have even used it to take a few scuff marks off of the hull.
Forget all of that expensive marine stuff and go to the laundry section of your local grocery store.

regards,
It'll do

Waxing Frenzy! Not only will it clean the transom; it will make cleaning it next time much, much easier. You should be able to just wipe it off with a damp cloth. Clean and protect in one step....and get back to boating!!