Lens focus ring sticky degrading rubber

[bobakman]

I have EF lenses some that were included in my kits and another the 70-300 that I purchased separately. 
I have noticed that the rubber outer covering of the focus rings only not the rubber on the body of the lenses, have deteriorated becoming sticky and soft with age.
These lenses have been stored when not in use in either my camera gear bag or separate lens cases.
These are the specific lenses and date of purchase below.
I am the original owner and have always had clean hands when using these lenses never any chemicals such as Insect repellant or perfumes or cologne on my hands.
I have submitted service requests for all of these lenses to Canon and am awaiting a resolution.
Has anyone else had this issue with their Canon Lenses?
Video link here: https://youtu.be/tK24Y3TMTm4
Thanks, Bob

EF-S 18-135mm f/3.5-5.6 IS STM. 2013-01-22

EF-S 18-55mm f/3.5-5.6 IS STM. 2013-06-03

EF 70-300mm f/4-5.6 IS USM. 2013-06-03

[deebatman316]

I’ve never had an issue with sticky rubber on lenses. My oldest lens which dates back to the 80s doesn’t suffer from this. My old EOS 40D body is sticky though. I also believe that Canon has discontinued support on the EF 70-300mm Mark I USM lens.

[normadel]

Use Isopropyl (rubbing) alcohol to clean the rubber parts.

Other chemicals can damage the rubber. 

The problem has nothing to do with cleanliness or storage in cases or not. It's an age and exposure to air thing. Lots of rubber-type coatings are subject to it....camera bodies, lenses, laptop computers, hand tools etc. Some coatings do it, some don't, to varying degrees.

[bobakman]

Yes the 70-300 has reached "The end of its service life." according to the Canon website. Though the end of its useful life has yet to be reached. I still consider this to be a manufacturing defect due to  poor materials selection of the specific rubber that was used on the focus rings. The rubber currently that was used on the lens bodies is not exhibiting this same issue.
I was E-Mailed by Canon and told to submit a repair request which I did and the quote I received for repair of both lenses still within their service life is $420.51.
I will reach out to Canon again and see if they will consider "particapating in the repair."
It can never hurt to ask. Canon has always done right by me and I am hoping this will be no different.
Bob

[ebiggs1]

"Use Isopropyl (rubbing) alcohol to clean the rubber parts."

That won't help. I have seen this happen on several different lens models. Replacement is the only real fix. You can pit tape around it. Something like tennis racket handle gripe tape will work. Sorta!

[bobakman]

Exactly what I am thinking either replacing the rubber or placing another cover material over it, leaning towards total replacement anything else is just temporary.
I see the same effect on rubber belts in stereo systems I have repaired. The rubber actually turns into a semi liquid almost like a grease the rubber on my two lenses is getting that way when it gets shiny it gets softer and all the alcohol does at that point is remove rubber until none is eventually left sadly.
Bob