Talking about cleaning heatsinks, guess what I use to clean heatsink base and CPU IHS...

I use minyak kapak..... Yes, minyak kapak (Axe Branded Medicated Oil). 
Just put one or two drops onto a tissue paper and wipe it over the heatsink base or CPU IHS top. It cleans pretty well but leaves a little oil on the surface. So, grab another clean tissue and wipe away the oil. Go give it a try and restore that shine back to your heatsink/CPU!

Minyak kapak good for nose blocks, headaches, etc and now cleaning heatsinks too! No kidding~ 

Because minyak kapak contains methyl salicylate, which is a sort of liquid ester. Ester is from an organic acid and an alcohol. So, this makes the minyak kapak carry certain percentage of alcohol.
Not really, coz I just use one or two drops only. IIRC, Arctic Cleaner has stronger smell right?
Well, if it cleans well... I don't see any reason why it could affect the TIM performance.

Some update on Zalman STG1:

Before using Zalman STG1, Used stock intel TIM
Idle 37'C Full Load 57'C

After applying Zalman STG1

1st Day
idle 47'C Full Load 66-68'C

After 8 days of casual computing..
idle 38'C Full Load 57-58'C

so i think i can conclude that Zalman STG1 need time to sink in before it will bring down the temp. besides that, zalman's performance not that impressive where it is on par with my previous stock TIM from intel. probably zalman stg1 dont work too well with Intel 478 Stock Cooler.