That looks like something I had several years ago. They were great for feeding my baby praying mantis, but never came back after that year. Didn't notice any damage from them (and there were LOTS of them!)

I tried to rinse them off, ==>>> its more of a blasting them off ... not just a dip and rinse .... indoors i would use the kitchen sink.. if you have a hard enough spray ... or the shower if you have a hand shower head .... you want enough pressure.. just short of injuring too many leaves .. the last pic above.. 'looks' heavily stippled on the back of the leaf.. if so .... you are going to have to be pretty aggressive .. if you could do it outdoors.. the hose would even work ... there are a host of things you could use on non-edible plants .... so thats out ... as to doing it by hand... well ... using the old cost benefit ratio ... it might be cheaper the throw them out ... and go buy some new herb plants .. rather than spend hours trying to do it by hand .... most likely ... you will have to do this once a week until you are sure they ... and all the generations are gone ... ken

@Vicky Renee OMG this is one fear that I had to make myself overcome when I started gardening (and am still working on it...) My coworker who is an avid gardener always laugh at how "urban" i am lol She talks about giving slugs "tummy tucks"......I don't think I'll be doing that anytime soon lol

Another pic in case it’s useful....