Old Norse spellings weren't even consistent at the time, and the Norse languages have different spellings (mainly divided between East and West Old Norse), also depending if you're using modern or old spelling, and that's not even talking about non-Norse languages.
So, as a Swede, I can usually recognise the words if they're somewhat similar. I used to be able to read some Old Norse (I've read the Poetic Edda in the original language), and I can sort of parse runes (although most times that happens is in manga where I determine whether they can be read or just random, and in the former case it's mostly English, though I've seen Latin and French).