For Helmet:
First, the preventive method. Helmets have a notorious way of getting all smelly with sweat, oil(for those who uses hair oil), and dirt. I don't use oil, but still I sweat, especially on summer. I find the best way of keeping my helmet clean as long as possible is by using cotton Balaclava, especially on hot days. I simply clean the Balaclava once or twice a week. My helmet's inners are still clean and fresh for months.
For cleaning the outer shell I simply use damp cloth and wipe them. I found partly damp tissue paper especially good for cleaning visor.
Now for the inner parts, Its somewhat crude but effective. My inner paddings are removable so I remove them and clean it with detergent along with my other clothes in the washing machine
. Most importantly I spin them dry. Since paddings are thick, it takes very long to dry without machine spin. squeezing/twisting is a no no.
Ah! but thats not all. Unfortunately, not all the inner parts are removable (at least in my case). So I dunk the entire helmet in detergent water in a HUGE bucket. This cleaning is only once in a long while. After cleaning, I use piece of cloth to absorb as much water out of it as possible as use hair blower on it at medium setting. I don't like things to remain damp for long. The straps can be cleaned easily with soap & water any time. And No! it wont fit inside the washing machine spinner.
Gloves:
Been using sneakers all my life. My gloves are not very different, so I figured cleaning them can be done by same method. Dunk it in detergent water in a bucket. After washing, machine spin dry. Voila.
Jacket (Mesh):
First remove all paddings, then machine wash along with other clothes. Not forgetting machine spin dry. I can wear it within minutes
. Been doing the same with my bags for years. They are more or less the same materials...so.
Jacket gets embarassingly dirty within a week (I use daily). I dust them every day but theres a limit to my tolerance.
Knee pads: Too new to comment
No riding shoes, no riding pants, no one piece riding suit.
Oh! almost forgot, My tank bag. Another one that gets dirty as hell within a week. Machine wash and....you know.
Told ya! its crude. Not recommending to anyone. Just posting what I do. No problems so far.