Okay, not exactly a creative repair but I still found it fun. It's an old razor that was given to me by my grandfather (now deceased) quite some time ago. It never held much of a charge so I decided to fix that.
Opening it up was fairly easy. The problem is immediately obvious with corrosion spotted on a battery terminal. The razor is very much built to a price. The motor is a cheap commodity chinesum motor and same for the battery. Strangely though, even though the PCB is single-sided they decided to spend the few extra cents on an FR4 PCB.
Since the battery was affixed to the PCB with some compound I decided to cut the leads and then desolder the leads. I used a manual solder sucker and some pliers to remove the clinched leads which worked out fine (in no small part due to the slots not being plated.)
I then proceeded to put the replacement battery in place and soldered that in. I reassembled everything and charged the razor. Works just fine (other than the motor acting up a little bit at times.)