The best bit of decanter (or wine glass) cleaning advice I've ever been given was from Maximilian Riedel himself and was "Never do the washing up after more than two glasses of wine!"
I've had a couple of emails from customers wanting advice on how to clean their Riedel decanters and this made me aware that although I've previously written about how and why you should decant, I've never given any cleaning advice.
The first (and most important) step is don’t let red wine sit in a decanter overnight, empty and rinse with warm water.
If you are washing your decanter straight after use, it should only require warm water. Depending on the hardness or quality of your tap water, I’d recommend using distilled water as highly alkaline water can cause cloudiness. Distilled water also doesn’t have any aroma or contain minerals, which will help prevent watermarks when drying.
Take care not to knock the spout of your decanter on the tap!
Avoid using dish washing soap or detergent in your decanter, as it can be very difficult to remove all traces.
If you’ve enjoyed a couple of bottles over the course of an evening, I recommend rinsing any leftover wine out of your decanter and upending a bottle of carbonated water (such as soda water) into the decanter to sit overnight. Rinse this out in the morning, with a steadier hand!
For persistent red wine stains, fill the decanter with warm (or even hot) white vinegar and soak until removed, then rinse well and allow to air dry (I sometimes use a warm hair dryer to speed up the process). For particularly stubborn staining, I recommend using denture cleaning tablets. Dissolve the tablets in water as suggested on the packet, and soak until the stains are gone. Rinse well and dry as above.
Use a Riedel Microfibre Polishing Cloth to dry and polish reachable areas of the decanter, for a perfect sparkling finish.
If the design of your decanter allows (i.e. no small "tails" where things can get stuck, such as in the Mamba, Eve, Curly etc.) then Riedel bottle cleaner beads are a must for keeping your decanter sparkling clean. Using them couldn't be simpler - fill the decanter up halfway with water, add the beads, swish them around for a couple of minutes and that's it - they remove all dirt, residue, sediment and stains. Then just carefully empty the beads into a mesh strainer, rinse then dry them and put them back in the box ready to be used again.