Assalaamu alaykum wa rahmatullaahi wa barakaatuh What is the ruling on purity of objects, surfaces, on absolutely anything and everywhere, if najasah is not washed or wiped but there exists no signs anymore.Used to think that things can be najis and transfer even if looks completely normal

Everything is pure by default, so nothing is judged impure unless you are certain impurity reached it, and dry upon dry is pure. As for impurity that dried until no trace of it remained, the scholars differ: some held that water is still needed, and others held that once it and its trace are gone by any means, the place is pure.