vaginapagina | Cleaning dried blood from underwear?

A while ago I got my period early and ruined a pair of beautiful new panties. I threw them in my laundry basket but then piles of other stuff ended up in there on top of them and I forgot about them. They ended up all the way at the bottom. I have a ton of laundry and it takes forever to get through it all, so I didn't find them again until today, about a month and a half later. Obviously the blood is completely dried in. I know that I should throw them away, but they're so pretty! Also, I'm a sentimental hoarder and these were the first pair of panties my boyfriend bought for me, so I desperately want to keep them.

How do I get this blood out? Is there a way? I know how to get blood off when the spill has only just happened, I do that all the time, but I've never tried to clean dried blood. Is there anything I can soak them in that will clean them? Or are they unsalvageable at this point?

EDIT -- Also, thank you for all your help with my most recent question. I am horrible at replying but I do very much appreciate your responses.