Thermolite vs Merino

If you wanna spend the money use Tech Wash by NikWax to wash your Merino and synth base layers in. If you want to achieve the same without spending money, use soap flakes, good old fashioned soap flakes from the supermarket/ironmonger/haberdashery store. This is 100% the same deal as Tech Wash. I've found both are the best at getting the whiff out of base layers, but I never machine wash Merino, despite people saying you can....

Icebreaker Merino by the way is the good stuff.

Base wash is better, it has stronger anti-bacterial properties, tech wash is OK however, i've used it as well when i've run out of Base Wash.