How do you get the black/purple stains from shorts/bibs out of the white saddle. What cleans white bars tape too?
Simple green works. Or white shoe polish.
Might I suggest 2-ply?
Couldn’t help it… yeah, it’s a bear. If you use any sort of cleaner, re-moisturize the leather so it doesn’t crack. I’m finding that rubbing in a bit of chamois cream right after cleaning works, and that’s what’s being ground in during a ride anyhow.
As said above, Simple Green works wonders. I use Simple Green and a dish-washing sponge. Makes the white tape look almost new. The saddle is a bit more difficult, but, it works on that as well.
Also, the blue liquid dish soap makes a great cleaning agent.
Westley’s Bleach White. Old product used to be used for white walls on car tires. Works much better than Simple Green (a degreaser).
How is the new bike build going?
Che-you
I don’t worry about the white saddle. And when the white tape is dirty I change it. I’ve never washed bar tape not a saddle.
How is the new bike build going?
Che-you
S-L-O-W 
Parts arriving in daily, but on vacation to the islands with the family. Took me a while to get the SRAM Red kit w/ the crank I wanted (172.5 52/36). Training/road wheels from the UK (new Dura Ace carbon fiber bonded things that are REALLY hard to come by). New Fizik Antares saddle looks nice though 
Very very nice .
Just got my road bike back from my LBS and my white handlebar tapewas pretty filthy (it was new when I brought my bike in for some adjustments). I usually just toss dirty tapes and just roll some fresh new ones on, but couldn’t justify it this time. I squirted some blue dawn into a pint of hot water and started scrubbing with a white wash cloth. After several minutes, my tape looked like new again The dawn got rid of the grease and dirt left by my mech. Washing white tape really works - just remember to wipe it down several times with a wet clean washcloth when you’re done cleaning it to rinse away any soapy residue.
As for my white saddle, I think it’s pretty hard to clean once the damage has been done, which is why I keep baby wipes/wet wipes next to my bike. Whenever I get back from a ride, I make a habit of wiping down my saddle and helmet interior. No problems since I’ve adopted this habit.