lens haze again

**bill kehoe** · 15-Oct-2009, 10:22

i just received a 300mm congo lens yesterday. coating much of the surface of the rear element closest to the shutter (ie. accessible) is a whitish haze that closely resembles the kind of calcium deposits hard water leaves on glass shower doors. it can be felt. as far as i can tell it is on the one surface only. the rest of the lens and shutter looks perfect. there were a few different-looking blotches on the inside of the front element but those cleaned right off with lens cleaner. the following nostrums gleaned from elsewhere on the web yielded no detectable results: windex with ammonia, vinegar, hydrogen peroxide, naphtha, isopropul alcohol.
the lens came from florida and because of deteriorated foam padding in an accompanying filter case, i suspect the lens was left in a car's trunk in the sun for an extended period of time, causing humidity to get inside the lens and leave some sort of chemical deposit. i don't really want the expense of a professional cleaning or the hassle of returning the lens. i'm thinking of trying a decalcifying cleaner but thought i'd seek other opinions before running that risk. any input would be appreciated. thanks for reading this.

**Mike1234** · 15-Oct-2009, 10:30

Man, if I was in your situation that lens would go back so fast to the seller for a FULL refund including shipping both ways... it would make your head spin. This is assuming he/she misrepresented the item.

**GPS** · 15-Oct-2009, 10:58

If a longer exposure to vinegar didn't help then it is not a calcium deposit.

**Toyon** · 15-Oct-2009, 12:17

The author of the lens Vade Mecum recommends Brass Polish (applied to glass only) as a way to remove some types of haze.

**bill kehoe** · 16-Oct-2009, 07:52

for the record, mouthwash didn't work either (from the cooke thread) although it did seem to spread the haze around, for some reason. however, brasso worked great. it took 3 applications but probably would have taken less if i'd actually been patient and followed the instructions. no sign of scratching with an 8x loupe. either there's no multicoating on that particular surface or the polish didn't hurt it. my purchase is officially back from the "good deal" category to the " great deal" one. thank you Lens Vade Mecum, toyon, and all other contributors.