How would one clean 20-year old gunk off a lens mount?

Sagitta · 10-20-2012, 12:48 PM

I picked up an old Sears 135mm f/2.8 macro lens a while back, and upon removing the rear cap discovered the lens had been put away with tape or glue or *something* inside the cap, which completely covered the mount.

As far as I can tell the entire camera bag this lens was in and its contents had been put on a shelf back around 1989 until finding its way to Goodwill where I picked it up for a song, so the lens has probably been gooed for over two decades.

Its very thick and sticky, but fortunately only is on the mount itself - the glass itself seems flawless (I actually wonder if the lens has ever been used more than once or twice, other than being gooed up it looks brand new).

My question is has anyone ever had experience with this kind of situation? My instinct is to just buy some acetone and dip the lens, but I can't afford to get anything caustic on the rear element because of obvious reasons. On the plus side, the rear element sits very far away from the mount so splashing might not be THAT serious an issue if I use something nasty to clean it.

Looking at that mount, I was fully expecting the lens to be a complete dud. I was surprised when I realized it probably has the best conditioned glass of anything I own outside the kit lens (which is the only one I acquired new)

Last edited by Sagitta; 10-20-2012 at 12:59 PM.

**THoog** · 10-20-2012, 01:22 PM

Can't see the pix, but the mount plate can probably be removed just by removing 3-4 screws and dunked w/o risking the lens. If acetone, alcohol, naptha (lighter fluid), or soap & hot water, or combinations of the above don't work, I'd try soaking overnight in SimpleGreen cleaner or something like that.

**Ex Finn.** · 10-20-2012, 01:27 PM

Your images are set to "private" on flickr. I would put some WD-40 on a Q-tip or a cloth and rub the mount clean.

**jatrax** · 10-20-2012, 07:37 PM

Goo-gone works a treat. Cannot see the pics but I agree with the above if you can remove the mount I would start there. Use your cleaner of choice and work slowly.

Sagitta · 10-20-2012, 08:47 PM

Fixed the privacy issue.

Its looking like its basically what I was trying to avoid - removing the mount to clean it that way.

I've come to dislike removing lens mounts simply because I tend to have bad luck when I do.

**THoog** · 10-20-2012, 09:54 PM

I hear you on removing mounts, tho' that one looks like the plate could come off without affecting anything else (I find older ones to be easier - less fiddly bits to worry about). If you take your time with a LOT of Q-tips dampened (not dripping) with whatever solvent works, you can probably get the gunk off that way.

Sliver-Surfer · 10-20-2012, 10:35 PM

99% Isopropyl Alcohol mount bath with it still attached is fine. Place it in a plastic or glass container with something plastic or glass to support the lens in a way that the aperture tab is not stressed and fill the container up to the top of the mount. a few hours should do then wipe off. I actually immersed a helios for an entire week with no ill effect.
****Dont use less than 99%

vonBaloney · 10-20-2012, 11:47 PM

Use acetone, but don't dip it -- just use a q-tip and keep working on it with small amounts slowly. If you think it is going to leak into the lens, simply hold it up with the mount pointing down so it can't. Rubbing alcohol will work ok, but maybe not as quick as the acetone. If you need something stronger, use lighter fluid (naptha). Which is what is in the goo removers, but is more expensive than lighter fluid I think. It should come off fairly easily from metal (plastic can be tougher).

10-20-2012, 12:48 PM	#1
Sagitta Veteran Member Join Date: Feb 2011 Location: Maine Photos: Gallery Posts: 3,081	How would one clean 20-year old gunk off a lens mount? I picked up an old Sears 135mm f/2.8 macro lens a while back, and upon removing the rear cap discovered the lens had been put away with tape or glue or something inside the cap, which completely covered the mount. As far as I can tell the entire camera bag this lens was in and its contents had been put on a shelf back around 1989 until finding its way to Goodwill where I picked it up for a song, so the lens has probably been gooed for over two decades. Its very thick and sticky, but fortunately only is on the mount itself - the glass itself seems flawless (I actually wonder if the lens has ever been used more than once or twice, other than being gooed up it looks brand new). My question is has anyone ever had experience with this kind of situation? My instinct is to just buy some acetone and dip the lens, but I can't afford to get anything caustic on the rear element because of obvious reasons. On the plus side, the rear element sits very far away from the mount so splashing might not be THAT serious an issue if I use something nasty to clean it. Looking at that mount, I was fully expecting the lens to be a complete dud. I was surprised when I realized it probably has the best conditioned glass of anything I own outside the kit lens (which is the only one I acquired new) Last edited by Sagitta; 10-20-2012 at 12:59 PM.

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10-20-2012, 01:22 PM	#2
THoog Loyal Site Supporter Join Date: Aug 2012 Location: North Carolina Photos: Gallery \| Albums Posts: 3,685	Can't see the pix, but the mount plate can probably be removed just by removing 3-4 screws and dunked w/o risking the lens. If acetone, alcohol, naptha (lighter fluid), or soap & hot water, or combinations of the above don't work, I'd try soaking overnight in SimpleGreen cleaner or something like that.

10-20-2012, 01:27 PM	#3
Ex Finn. Site Supporter Join Date: Nov 2007 Location: Southern Maryland. Espoo. Kouvola. Photos: Gallery \| Albums Posts: 7,975	Your images are set to "private" on flickr. I would put some WD-40 on a Q-tip or a cloth and rub the mount clean.

10-20-2012, 07:37 PM	#4
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Goo-gone works a treat. Cannot see the pics but I agree with the above if you can remove the mount I would start there. Use your cleaner of choice and work slowly.

10-20-2012, 08:47 PM	#5
Sagitta Veteran Member Join Date: Feb 2011 Location: Maine Photos: Gallery Posts: 3,081 Original Poster	Fixed the privacy issue. Its looking like its basically what I was trying to avoid - removing the mount to clean it that way. I've come to dislike removing lens mounts simply because I tend to have bad luck when I do.

10-20-2012, 09:54 PM	#6
THoog Loyal Site Supporter Join Date: Aug 2012 Location: North Carolina Photos: Gallery \| Albums Posts: 3,685	I hear you on removing mounts, tho' that one looks like the plate could come off without affecting anything else (I find older ones to be easier - less fiddly bits to worry about). If you take your time with a LOT of Q-tips dampened (not dripping) with whatever solvent works, you can probably get the gunk off that way.

10-20-2012, 10:35 PM	#7
Sliver-Surfer Pentaxian Join Date: Sep 2011 Posts: 1,558	99% Isopropyl Alcohol mount bath with it still attached is fine. Place it in a plastic or glass container with something plastic or glass to support the lens in a way that the aperture tab is not stressed and fill the container up to the top of the mount. a few hours should do then wipe off. I actually immersed a helios for an entire week with no ill effect. ****Dont use less than 99%

10-20-2012, 11:47 PM	#8
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	Use acetone, but don't dip it -- just use a q-tip and keep working on it with small amounts slowly. If you think it is going to leak into the lens, simply hold it up with the mount pointing down so it can't. Rubbing alcohol will work ok, but maybe not as quick as the acetone. If you need something stronger, use lighter fluid (naptha). Which is what is in the goo removers, but is more expensive than lighter fluid I think. It should come off fairly easily from metal (plastic can be tougher).