Help identify lens spots

Hi, just got an old LTM Canon 50mm lens - and its back element have these weird spots on the inside surface; see the picture attached. I opened the back element, cleaned it with windex and filter, but the spots are still there. Can anyone help me identify what it is and how to get rid of it? Thanks in advance.

fungus

fungus

Could be fungus, but I don't think it's active if it is (was); if the glass is etched, there's not much to do about it. The pattern of the marks make me wonder if it isn't mechanical, i.e., overly-aggressive cleaning. Fungus usually starts around the edges, not randomly scattered around the center of the lens (though it's possible, of course). In any case, the scratches make it clear someone's been in there before you.

thanks guys, looks like the lens is FUBAR, though sold as "cosmetically 9.5/10" condition on ebay will try to get it returned.

btw, i the flaws in the lens become apparent only with the flash pic. I will be asking sellers in the future to send me pics of the lens using the flash.