How to clean Haze?

inombrable · Joined: 20 Mar 2012 Posts: 545 Location: Salamanca, Mexico

I got a returned lens (soligor c/d 35-105) because of haze, i didnt realized before selling but after return i checked with a torchlight and indeed there is an internal element with a lot of dots creating haze.

Anyway, after that i got curious and started to do some test on a couple of very hazy elements i have from 2 very cheap lenses, the result .... no success

i know there are different origins to haze and some are more difficult than others, my question is, what have you used to clean haze?

I will list what i've tried so far (in most cases highly concentrated, from my lab):

Cold cream
Vinegar
Isopropanol
Acetone
Sodium hidroxide 5M
Potassium hidroxide 5M
Dimethyl Sulfoxide
Chlorhidric acid (.1, 1 and 5M)
Nitric acid 5M
A combination of Sulphuric acid and Chlorhidric acid

The last one was quite strong, i left it overnight because i forgot about it and the next day i found out that the glass got chipped but the haze was INTACT !!!!!!!

Any other ideas?

ForenSeil · Joined: 15 Apr 2011 Posts: 2726 Location: Kiel, Germany.

I think there's no way to remove haze which is deep inside the lenses.
Strong lyes like NaOH or KOH are able to release Ca2+, silicate- and other ions, so they should even boost the haze if the contact is long enough. Acids are able to remove many coating ingriedients like MgF2 etc.

Once I was able to remove haze with hot 60-90° petrol ether. The haze was caused by condensation of softeners or something similar inside the lens and was very superficial.

I know that many sperficial hazes can be removed by polishing with cerium oxide on pitch medium with creasing which has to be casted into about the negative form of the element.
Example (skip to 0:25)
http://www.youtube.com/watch?v=4f9RJnB_TFU

It's a well known method for the last step for making of own mirror lenses/telescopes, to get a perfect surface before adding the silver layer.