Whatever it is, it's tough to clean when it builds up. Isopropyl alcohol pads aren't effective.

Chemically, it has some resin, oil, and essential oil, but it's mostly sugars AFAIK. As it dries out & gets exposed to oxygen & light, some of it polymerizes & encapsulates itself or forms a crust, so requires mechanical removal (brushing) rather than simply dissolving it.

I switched to using cheap heavy duty scissors rather than gum up good pruners. There's a couple dozen plants in my small 50 ft wide lot. They're the "common" sunflower that grows wild in NE San Antonio, that start to slowly shrivel up in mid-summer. I occasionally get skin irritation from just brushing up against young growing plants early in the season.