OK. I get it now. I repeated the process, and then waited for the lens to dry. There were no spots. Instead of using distilled water, I used RO water from the system I bought at Home Depot and installed under my kitchen sink. It worked just fine.
This time, however, I let the lens dry after step 1, before proceeding to step 2. Using a flashlight, I could see that there was still dust on the lens. This is what I suspected. Rinsing with warm water alone did not remove all the dust. In my opinion, this is a flaw in this method.
If the lens still has dust on it, then rubbing the lens with a cloth in step 2 will scratch the very thin anti-reflection coating on the lens. Even though the cloth is wet, you are still pushing the lens cloth onto the dusty lens and rubbing the dust around the lens. The wet dust is abrasive, just like wet sandpaper is abrasive. The damage won't be noticable after one cleaning process, but it will build up over time with many cleanings. I recommend that you find a way to remove the dust before going after the greasy smudges, fingerprints, etc. This is essentilly what tulku described in his post when he used a wet Q-tip to wipe the lens with one pass.
If all I had was a lens cloth, I would very gently wipe the lens once from one side to the other using a wet lens cloth. Then fold the lens cloth in half and rub the lens to remove smudges. After that, I would discard or wash the lens cloth, because I won't remember later which side has the dust on it, and it's been thoroughly contaminated with oils from my fingers.
I just knew Bruce will formulate some kind of conclusion like this.
I voted for my "FREEDOM", "GUNS", and "MONEY" - keep the change - UNK.
"I am always proud of my country!"
"Leadership Rule #2: Don't be an edited." - Maj Gen Burton Field.
I forgot to say one thing. I was surprised at how clean the objective lenses came out using Losthwy's process. I mean edge to edge clean. The inside of the objective and eyepiece bells were clean too. I have to work pretty hard with lens tissue to get lenses that clean.
This thread seemed to get derailed at the beginning. It's easy to pick at someone else's methods. I think Losthwy is on to something here. The only change a would recommend is to gently wipe off the dust before rubbing the lens with a cloth. Otherwise, I think this method is brilliant and worth doing whenever you have the chance.
FWIW, I've been using isopropyl alcohol to clean precision laboratory lenses and other optics for decades. When used as a cleaner, It will not harm optics, plastics or rubber. It's also reasonably safe to handle.
Have a couple beers and whiz on your bino's. That will remove the smudges and leave them smelling pristine.....
I use the kit that came with my Nikon DSLR for lens cleaning. I believe it's alcohol and a micro fiber cloth....
My eye glasses get run under the shower and dried with a bath towl along with my body....
I would but Im not a beer drinker....more Maker's Mark or Jack Daniels man.
This thread has taught me more than 1 lesson. Reading thru it...Ive found that if some of these yawhoos can hachet ass up a simple job of cleaning important lenses....Id sure as hell never let those people work on a rifle of mine!