I purchased this 130XE as a working unit to get a look at it and try to retro-bright the keys on the keyboard.  I found the unit very clean on the inside but the power led on the keyboard was not working.  In trying to retro-bright the keyboard I tried using Hydrogen Peroxide paste directly on the keys and tried soaking the keys in the cream mixed with hot water.  I was able to get the dark keys a bit lighter but it is still browned.