I still have tubed tires on my bike. When I get a flat, I patch the tube. Finding the hole is no problem, but keeping track of it is. What can I use to mark the rubber tube? I tried crayon, but that doesn’t work. Will a grease pencil work? Or something else?
Sharpies are great, but a lot of machinery is black, or is in the dark. I keep a silver sharpie around for just this.
I don’t know much about this, but can you get a patch that is a different colour to the tyre?
I use chalk, the few tyre repair kits I have bought include a piece
A grease pencil works great. One advantage is that it will write on a wet tire or tube if you have use the soapy-water method to find a pinhole. Light colors work best, of course.
The color of the patch is irrelevant. I’m marking the tube before I’ve put on the patch. OK, grease pencil, chalk, or Sharpie. Thanks. And yes, I know about getting a light colored marker.
PS Anyone want to buy a 24-pack of crayons? The white has been slightly used, otherwise pristine. 
It’s been a long time since I’ve patched a bike tire, but back when I always just used regular blue ballpoint pens as markers. The contrast to the grey rubber wasn’t super sharp, but sufficient.
Use a little piece of sandpaper to rough up the surface immediately around the hole (this can be done when wet). When dry, it should be possible to find the slightly rough patch (and the surface roughness will help the patch to adhere.)
Try a paint marker. They’re little tubes like a fat ink pen that leave a dot of paint behind. In my experience, the paint readily sticks to most anything, including rubber, but YMMV.
Maybe a piece of tape.