The oldest, safest cleaning method is a couple tablespoons of vinegar and warm water. Use a soft toothbrush. The grey brown condition may be permanent due to the wear.

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am not sure about lcd screen protectors from canon, but sony do have them and all you have to do is specify lcd screen size
just got mine for my sony dsc t70, 3″ screen size
and believe me, i needed it pretty badly cause it’s touchscreen operated and i gladly parted with $7 for that
they also have them for 2.5″ & 3.5″ … that i know of

not sure about your screen size, but i guess it’s 2.7″ > in which case if sony does not have a 2.7″, you can buy the 3″ & cut out the extra portion with a pair of fine scissors

just sharing my limited knowledge, cause there’s no reason why canon should not be having it … just that i do not know

as far as cases, plenty many optionals available and sure something should fit just right … and all the best on that

edit:
supplies and accessories for your sx100
http://estore.usa.canon.com/cigSeeAllSuppliesAndAccessories.asp?product=2091B001&src=sna_estore&WT.mc_id=C000000
note that the Deluxe Soft Case PSC-100 $19.99 is compatible with the sx100 only … so just right that !

and as far as your lcd screen protector, 2.5″
closest i could locate was from sony india
http://www.sony.co.in/product/pck-l25/sku/pck-l25%2B%2B%2B%2B%2Bae?site=hp_en_IN_i

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I got a hard cover case, just from a cart in the mall.. It’s solid plastic, the only color they had at the time was white. I may get another one.. so far it’s not well made, cracked once, and i was able to fix it with super glue.

Again the back half cracked and rendered that part of it unusable. But the solid plastic cases are in two parts, on for the front and one for the back, so the front is still protected which is the most important.

So far I’m not sure about a good case for the EnV because of how it flips open. You’d do well with a silicone or I went to Wal-Mart and got a $5 clip on cell phone pouch that it fits well in to and is completely protected when inside.

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Skip it. Anyone with previous experience, distribution connections and the funding to start up has already done it. You’ll get killed trying to compete without experience.

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