Cannot remove fungus in FD 28mm/2.8 sc

<p>Hi there, I've try to remove the fungus from the lens. The only issue left is the fungus on the rear element seems to be there.<br />There are 3 attempts I have done.<br /><br />1. Hydrogen Peroxide + Ammonia (1:1) at 2 minutes <br />2. Hydrogen Peroxide + Ammonia (1:1) at 3 minutes also<br />3. Hydrogen Peroxide + Ammonia (2:3) at 2 minutes<br /><br />But non of these precess come to a beautifully finished.<br /><br />Need some suggestion.<br /><br />Thank you.<br /><br /></p>

<p>If the fungus has etched the glass, there is nothing you can do short of sending it to a specialist for removal and recoating...all quite expensive. This isn't a particularly expensive lens, so you might want to pick up another copy and switch elements.</p>

<p>One of the advantages to the old "uncoated" lenses from the 1930's & 1940's is that when they were attacked by fungus, you could take them apart, clean them up, and they were as good as new.</p>

<p>Unfortunately with newer coated lenses, the fungus attacks the coatings. So you can get rid of the fungus, but now you have etched coatings on the elements. What Stephen said, the only real fix is to have the lenses stripped of their coatings and recoated.</p>