From HomePod mini, to Google Nest Audio and on to Amazon Echo, if you have been using one to power your smart home experience for a decent period of time then it's almost certainly going to be looking a little worse for wear.
The best smart speakers all come in attractive-looking fabric covers, which look great in photos but definitely not so great after a few months around kids or in your kitchen getting splattered with oil and bolognese. And that's saying nothing of the build-up of dust and detritus that happens in every room.
I know this from bitter personal experience, having once put a white-coloured smart speaker in my kitchen. But it's a universal problem, and thankfully the nice people at The Verge have the solution to hairy HomePods, icky Echos and greasy Googles.
How to clean your smart speakers
The advice is consistent across manufacturers: don't reach for chemical sprays or other hardcore cleaning products and be very careful. For best results, use a microfibre cloth to wipe away dust and dirt; dampen but don't soak it if you want to get rid of stains. You'll find that'll get rid of the vast majority of marks, leaving your smart speaker shiny and new again.
There are two exceptions to that: kids and kitchens. I have both, and as a result, my tech is victim to food-covered fingers from the kids and flying fat from my skillet-cooked steaks. For those kinds of stains you might need to bring in the big guns, and by big guns, I mean a little Fairy Liquid or Dawn dish soap with a bit of warm water and a toothbrush. If even that's not enough a baking soda solution left for 20 minutes or so can remove very stubborn stains, but test it on a small area on the back of the speaker fabric first to make sure it doesn't affect the colour.
For grease, though, prevention is better than cure: once grease stains get into something they can be really hard to shift. You might find repositioning your speaker(s) to less dangerous places might save you a fair bit of scrubbing in the future.