How cleaning a 8x10 fresnel lens?

[fredludv]

Hi, I have a 810 sinar fresnel and standard that is very dirty from some type of dried developing liquid or similar (from previous owner), anyhow it comes off in dry chunks and in very small pieces, it is worst out in the corners, and around the standard. I have to get rid of all this oyherwise it will get into filmholders while shooting.
I think I have to use a piece of metal instrument first to scrape it off and then clean it with any kind of cleaning liquid..
Would Isopropyl work without damaging the glass?
Maby in the kitchen dishwashingmachine without powder.. ?

Any suggestions?

/Fredrik

[Andrew]

I've cleaned a couple of old graflex fresnels in warm soapy water using a soft cloth following the fresnel grooves without doing any obvious harm
if you scrape away with any sort of impliment you're likely to do damage so I'd try a long soak in warm water first and see how much comes away with that
and the fresnels tend to be plastic so I'd be wary of any sort of solvent

[fredludv]

Thanks Andrew, I´ll try a long soak in warm water first and see what happens..