i'm not sure whats available in your area, but mine looked very similar when i tore them apart, i use berrymans b12 chemtool for almost anything carb related. works great for old gas residue and removing anything stuck on i use a small brass brush, or stiff bristle plastic brush, most auto parts stores sell them in a 3 pack. just don't get that b12 on any diaphragms they will melt! when finished my floats only had minor stains left, but no build up
hope that helps
also if your carb boots are too stiff i just read a great trick to revive them is wintergreen oil and xylol solvent solution to soak them, from what i have read, very impressive results and much cheaper than replacing them. i believe there is a write up on here and sohc4.net if you want to look it up