pests Are these aphids?

[6StringFire]

I opted to kill 2 birds with one stone... well, 2 aphids.
I'd been researching and quite a few folks mentioned to "just shoot them off with a burst of water". Since this didn't appear to be a major infestation and luckily it's only one plant (out of 4), I filled the squirt bottle up with Epsom Salt infused distilled water and foliar fed / jet sprayed them off.

So far, that have not returned after this treatment. I lost some leaves, but I suspect they were compromised anyway. There's still a nice dense plant there. I'm not necessarily saying this is the solution - just that the bugs are no longer there.

I DO see remnants - small black - what almost look like egg sacks. They were there along with the aphids originally but were tough to blast off. Any ideas what these are?