For cleaning, 50/50 mixture of Simple Green and alcohol is very cost effective.
Cheap, but it can't be used during bowling.
After bowling, Clean & Dull, Hook-It or LMB International's ball cleaner are all much more effective. They all remove ground in oil lines that SG won't.
You can use the original formula simple green at anytime and it is legal. I'm not sure if your post was pertaining to mixing with alcohol or not using it in its original bottle. Those two things may make it illegal. Even though Isopropyl alcohol is legal at anytime as well.
But plain SG leaves a film. It then has to be cleaned off before you bowl with it.
Not enough of a film according to USBC. Or else it wouldn't be on the approved anytime list. I was told by USBC that was the reason that they moved Clean N Dull to the before and after list, because it left a film on the ball.
I'm not worried about what the USBC saw; I'm basing what I said on what I saw when I used it to clean my shield of some nasty stuff. It left a film that required alcohol to remove.
Clean and Dull has a proven track record.
Why did you say a mixture of simple green and iso alcohol couldn't be used during bowling, because it is a mixture? You could use simple green and then alcohol if you were worried about the film affecting your ball performance.
Because every mixture is, according to the USBC, a different chemical and has to be approved separately. Someone posted this a while back (maybe a year, maybe 18 months) and specifically asked that question of the USBC and was told any mixture they hadn't tested is not approved. So SG by itself is approved; SG plus anything else is not approved for use on a bowling ball at any time.
Besides all that, SG is simply not as good as Clean and Dull, Hook-It or LMB International High Performance ball cleaner. It's great on garage floors but not on bowling balls. If you want to use it, I'm the last person to stop you; I just can't recommend it personally.