I had to scrape a few off my horse this morning too. That time of year again
I use a bot knife, available at most tack/supply stores. You can also use anything with a nice clean edge. Your fingernail, a butter knife with a serrated edge, those grooming blocks work good too. The main thing is you want to scrape them off in an area away from where the horse eats. Preferably in a gravel or paved driveway or walkway.
I plan to worm this week and then again for bots after the first freeze. You want to wait till after the temps drop before giving a boticide wormer or they will just get them back.