How long to fix over carbed keg?

I have been away on vaccation for 2 weeks and came back to my 5 kegs are seriously overcarbed. Somehow I set my regulator to 20 psi and it has sat that way for 2 weeks. The beer is pouring with lots of foam and beer is flat. I just turned off my co2 tank and vented all the kegs.

I have a big party This Saturday.
My question is, how long will it take to bring down the co2 levels in the beer to about 2.3?
Can it be done in 2 or 3 days?

Also, what is the best procedure to do this? Should I just vent all the co2 from the kegs a few times a day and not attach the co2 at all?

The same way you can shake co2 into the beer, you can shake it out. You might try depressurizing, shake the keg, bleed again, shake, bleed etc. until the carbonation is where you want it to be. Let it sit a few minutes in between taste tests/shakes so that you do not overshoot it.

Search you tube but some guy stuck the long dip tube in the co2 side and pressurirzed it and released the over carb.

I would just keep all of the kegs off of the c02 and vent like crazy, like everytime you walk by. Test tomorrow and see where you're at. I would NOT shake or anything.

Is 2 days enough to fix it?

Assuming that you have some decent length lines, around 8-10', you should be able to get them pouring OK in two days. Leave the gas disconnected and vent often. To check progress, wait about an hour since the last time you vented and go ahead and try pouring. Make sure you pour about 2 ounces, drink it, then pour another few ounces to see if it's a controlled pour with some bubbles in the beer. If it's out of control and all head, vent the keg again and come back in an hour.

I tell ya, I'm having one heck of a 4th of July checking all this beer every hour It's a tough job

One keg got better already. the other 4 I'm still venting every hour.