Check out the camera repair site at mypentax.com. Cleaning a mirror safely is covered there. Essentially it is a cotton bud & alcohol thing, but there is a right way and a wrong way to do this.
Alcohol is specified for these cameras in the official Pentax service manual.
The viscous fluid method is called collodion cleaning. It works by gluing the dirt to a layer of nitrocellulose. (Collodion is a solution of nitrocellulose.) It is not perfect, it has it's risks especailly if the mirror has been marked in some way. This will provide a 'key' for the collodion, which could result in the peeling of the metal coating. It should only therefore be used when it is certian that this cannot occur. For most cameras this means you don't do it.
It will be done for proffessinal cameras which have been maintained by the tecnician, or for mirrors in the optical path where absolute cleaness is of vital important. It is also quicker than other methods and is the reason that it is done in these situations.
For most cameras this level of cleaness is not required, and even quite substantial marks are invisible or at least unubtrusive in practice. So in these cases the additional risk, and lower standard required maked it inapropriate.
Alcohol is specified for these cameras in the official Pentax service manual.
The viscous fluid method is called collodion cleaning. It works by gluing the dirt to a layer of nitrocellulose. (Collodion is a solution of nitrocellulose.) It is not perfect, it has it's risks especailly if the mirror has been marked in some way. This will provide a 'key' for the collodion, which could result in the peeling of the metal coating. It should only therefore be used when it is certian that this cannot occur. For most cameras this means you don't do it.
It will be done for proffessinal cameras which have been maintained by the tecnician, or for mirrors in the optical path where absolute cleaness is of vital important. It is also quicker than other methods and is the reason that it is done in these situations.
For most cameras this level of cleaness is not required, and even quite substantial marks are invisible or at least unubtrusive in practice. So in these cases the additional risk, and lower standard required maked it inapropriate.
Don't even think about cleaning the mirror in your SLR. For smudges and marks that can't be blown away with a handheld blower, you really need to have it cleaned by a repair shop. Most technicians clean mirrors with a special viscous fluid specially formulated to protect the fragile surface of the mirrors. Definitely do not attempt it with a standard lens cleaning solution or cloth as you could cause irreparable damage.
Keep in mind that this will not require disassembly of the camera, so the charge should be nominal
Answers & Comments
Check out the camera repair site at mypentax.com. Cleaning a mirror safely is covered there. Essentially it is a cotton bud & alcohol thing, but there is a right way and a wrong way to do this.
Alcohol is specified for these cameras in the official Pentax service manual.
The viscous fluid method is called collodion cleaning. It works by gluing the dirt to a layer of nitrocellulose. (Collodion is a solution of nitrocellulose.) It is not perfect, it has it's risks especailly if the mirror has been marked in some way. This will provide a 'key' for the collodion, which could result in the peeling of the metal coating. It should only therefore be used when it is certian that this cannot occur. For most cameras this means you don't do it.
It will be done for proffessinal cameras which have been maintained by the tecnician, or for mirrors in the optical path where absolute cleaness is of vital important. It is also quicker than other methods and is the reason that it is done in these situations.
For most cameras this level of cleaness is not required, and even quite substantial marks are invisible or at least unubtrusive in practice. So in these cases the additional risk, and lower standard required maked it inapropriate.
Don't even think about cleaning the mirror in your SLR. For smudges and marks that can't be blown away with a handheld blower, you really need to have it cleaned by a repair shop. Most technicians clean mirrors with a special viscous fluid specially formulated to protect the fragile surface of the mirrors. Definitely do not attempt it with a standard lens cleaning solution or cloth as you could cause irreparable damage.
Keep in mind that this will not require disassembly of the camera, so the charge should be nominal