Clean caulk on window outside

If you want to just clean it, try the Heavy Duty Mr. Clean Magic Eraser. Or see if you can cover the existing caulk with a new layer that you can wipe clean.

Looks like the whole window area could use a new coat of paint. Just wash it and paint over it. Caulk doesn't melt, but it does look like it was poorly done.

We had the same thing happen to our French doors at our former home. The factory-installed caulk (sealant) did, in fact, "melt" due to the intense sunlight that would beat down on that side of our house. The windows on our French doors were gas-insulated, double-paned ones, meaning that a layer of argon gas is sealed between the panes. When trying to address the melted sealant issue, you need to be careful that you don't disrupt the original sealant enough to break the factory seal. If the seal is broken, you will begin to notice condensation between the panes of glass. Then, you will have a much bigger problem to deal with. If you notice condensation, remember to check with the door manufacturer, company who installed them, and/or the builder as most of these types of doors come with a warranty which may cover repair or replacement for years after installation. Hope this helps!

Usually you have to use a razor knife/box cutter. Then you have to sand. You could electric sand with the edge. But cutting it out is the only way.

It depends on the caulk. Silicone caulk is cut out. Scrape, cut, scrape, cut and so on. You can also try DSR5 to remove silicone and siliconized caulk.

Some caulks can be removed with a heat gun, but it has little effect on silicone. Mineral oil/baby oil can also remove some latex caulks by softening the caulk and making it easier to scrape away.