Help me jumpstart my lithium ion battery! (Muvo Slim mp3)

[nobb]

Hi.
I have a Muvo Slim mp3 player which charges via usb, and today it just refused to charge. I knew instantly that it was because the player had been too deeply discharged and therefore the charging circuit was preventing it from charging. I measured the potential across the lithium ion battery and the reading was 3.2 volts. When I turn on the player, I get a low battery icon, and it turns off. When I connect the usb cable, the charging symbol does not show. I have noticed that some users have been sucessful in jumpstarting their lithium ion batteries. I have a variable voltage source so I set it to 3.7 volts and connected it to the lithium ion battery's electrodes. I waited for a minute and still, no luck in getting it to charge. I then did some more reading and I found a user suggesting to use 4.5 volts. So I did it at 4.5 volts. When doing this, I always keep my index finger on the battery so that I know when to stop incase my battery starts to heat up. When I used 4.5 volts, the battery started getting warm in 20 seconds. I was worried so I quickly stopped. I then quickly connected my player to my usb, and still no luck.

I am quite aware of the hazards of trying to jumpstart a lithium ion battery, but I would still like to give it another try. This time, I will do it in my concrete driveway so incase anything happens, atleast its not inside the house. I will also be far away when I do this. So my question is. Can anyone please recommend some strategies to try? What exact voltage should I use, and how long should I leave it connected? Right after I disconnect the voltage source, do I immediately connect my powered usb cable? Also, if a fire starts, what chemicals (household?) should I use to put out the fire? Would baking soda be ok for this purpose?

The mp3 player is pretty much useless without a battery, so I figure might as well try to get it working again. Even if it does go up in flames, atleast it will be a nice learning experience.