Not a new coin, but for some few days ago I held that low-priced coin, and then I used my nail to scratch the patina, and some of the patina fell off. I am just wondering: do you think this is applied patina? I have not bought it from the two infamous dealers in vcoins often accused of applying patina. Justin I, sear 63:
To me it looks to be a real desert patina. I have a couple where I have been able to scratch off a bit of the sand/dust with my finger nail.
It may be "applied" patina that is just some dirt/mud applied to better highlight the remaining details or it may be natural. If it came off with your fingernail it probably isn't one of the synthetic glue-based mixtures that some sellers use on their coins so really it's a personal preference thing if you want to remove it or not
Here's an example of one of mine (Heraclius and Heraclius Constantine) - does come off when scratched with a finger nail:
It does not look "applied" to me. Anyway, I would not remove it. The coin is so worn few details remain and the highlighting helps.