Most scopes that are older had their lenses laminated using a glue made from the sap of the Canadian Balsam tree. After a long time this glue breaks down and causes a cloudy view when you look through an older scope. To repair this problem each lens must be soaked in a strong chemical and the pieces seperated. All the glue must be removed before being relaminated. We only use a mil-spec glue for the relamination proscess. The lens is reglued and cured in a special press for 24 hours to make sure it is free of voids. Then cleaned and reinstalled in the scope.
There are two other kinds of lens haze or cloudy lens. One is caused by condensation from moisture condensing on the inside of the scope due to periodic maintenance not being performed on the scope. When assembling a scope; all threaded parts are coated with a special heavy grease to seal the threads and prevent gas leakage. This also prevents moisture from entering the scope. Once moisture enters the scope it must be dissasembled, cleaned and resealed. At this time it will also be purged of air and filled with dry nitrogen gas.
The third lens haze or cloudy lens is caused by one of three fungi. These are called Phycomycetes, Ascomycetes and fungi Imperfecti. These fungi can damage a lens beyond repair. The fungi produce an acid that will etch the coating or lens surface. If the lens has been etched by the fungi generally it is only repairable by replacing the lens with one not infected by fungi. If the lens is not damaged, it can be cleaned by; first soaking in a strong chemical to seperate the pieces of the lens, then the pieces must be cleaned of all glue and soaked in a strong solution of chemicals to remove all living and dead fungi, after this is done the lens is reglued, cured, and then inspected for clarity and voids in the glue.
When scopes were built in the early days the reticle or cross hairs were made from spider's web strands. The webs of the Brown Recluse Spider were collected carefully. They would wind the strands of the web on a stick. Just like you would kite string. It was found that the young recluse web strands were the strongest thinest material available at the time. Presently we use Chromaloy and have now turned to Tungsten to make our reticles. This material is much stronger then previous materals used. Many manufactures have turned to glass etched with a laser to produce reticles in their higher end scopes. This allows for more complex reticles, such as the tacticals.