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Nothing wrong with VD's products... I've found them to be the best solution for me.
Looks like you've captured some oil on your swab as you brought it in, and I'd guess it will take a few swipes to get rid.
Smear Away seems like a strange choice for a first time clean. I use Sensor Clean with the green swabs as I find them much easier to get good results with. (I don't like the orange type).
Follow their advice on solutions. They make different products because each has a different property. (Bit like how we use shampoo for our hair, soap for our hands and washing up liquid for our dishes... Certainly you can use soap for everything but it's not the best way...)
You may want to try swabbing a different direction and when you insert the swab, try turning it 45 deg to the sensor and only line it up when you're just above. This will help from touching the sides or mechanism where you possibly picked up oil.
If you're unsure, get it it cleaned professionally and just be careful next time...!