Dropping in attic identification

Could be a lizard, either gecko or skinks, doesn’t necessarily mean an infestation, they get pretty active in summertime tbh. Those geckos can fit damn near anywhere.

What size are the droppings?

You’d be hard pressed to keep out all those lizards. How many are you finding? You would know if you have an infestation in your hands, would be droppings everywhere. Scattered here and there is less of a worry, and if it’s lizards it’s preferable to mice or rodents - less damaging.

Gecko.

Correct about the white bit... shows that it,s lizard. Other reptiles are possible but very unlikely to be in attic.

Without a long biology lesson, reptiles and birds pass combined excrement that has kidney waste as uric acid salts (white stuff) and undigested food waste (brown stuff). A single body hole is used... the cloaca.

I get mostly geckos in my attic along with a few anoles. They climb the exterior wall and slip between the edge of the soffit and the wall.

All poop comes with the gut microbes of the maker. Some poop has pathogens. Best practice is don't handle and don't breathe dust if you sweep them up.