>>21507402If it stinks then it got put away humid and/or unwashed. Best to toss them and get new ones. If that's your photo then boiling the bottom tier will leave it much more waterlogged. Usually these need at least a couple of days, but if you're boiling the bottom then it'll need way longer, which means it spends days and days being wet so bacteria readily grow there. And they need to be lightly scrubbed with a soaped up brush immediately after use because the food will migrate into the bamboo and instantly grow microorganisms.
The yellow water is from the bamboo leeching into the water, especially if you're boiling the bottom tier. It's harmless but it does alter food flavor. Some argue it's an enhancement, and I agree for certain things. But it's not something you want on everything else. This is minimized by not boiling the bottom tier, only having them over steam when needed, and drying them out completely after the last use.
This is why I just use the metal steamer pot and only use these for backup. I've had mine for 3 years and they're fucked up in other ways, but they don't smell.