The reason is because we’re all washing too often at low temperatures or always using the quick cycle.
Bacteria, which produce gases that give off a bad smell, will survive a 30 degree wash, so when the water drains away, the bacteria are left behind to build up and grow in number inside the machine, hence the nasty niffs (and eventually black mould on the seal).
Do a ‘maintenance wash’: throw a cup of clear vinegar into the empty drum and run the machine on the hottest wash.
Thereafter, make sure you do a 60 degree wash once a week, particularly for towels and cotton sheets. Sweet smells guaranteed from now on.
There’s no need to resort to expensive, strong products to attack limescale.
Much better to stick to homemade remedies, which are just as effective, and a lot cheaper.
If your chrome showerhead is caked with scale, unscrew it, and steep overnight in a bowl containing half clear vinegar and half warm water. In the morning the scale will flake off and the head will only need a little rub with a cloth. Note: don’t use on special metal finishes, as vinegar can damage.
For scale in an enamel bath or porcelain sink, dampen a pumice stone and rub away at the mark. Don’t worry about scratching: the pumice is hard enough to deal with the scale but soft enough not to damage the surfaces