The way I've been doing it for 40+ years:........I use vacuum pump to get everything out of the reservoir, wipe the reservoir with cotton swabs (every nook and cranny), I don't disconnect the hose, I fill the reservoir with clean fluid, and pump, pump, pump, until I get clean fluid coming out of the bleed nipple (adding fluid as it goes down in the reservoir). It works for me. I change fluid once a year, and I never really encountered "slime/crud" in the reservoir, unless I purchased a bike that was neglected. "Brake cleaner"? No way Sir.