Do you spend a lot of time on the trainer? I had some severe headset and pedal/cleat damage the first winter I took it really seriously on the trainer. Now I keep a towel on/over the aerobars and make sure to take my shoes off the bike so it doesn't fuse together.

In what part of the country do you live? What is the distance between you and the ocean?

Have had a relatively new headset completely destroyed by sweat while indoor riding, don't do much riding indoors these days but always cover the headset up with electrical tape or plastic wrap when I do. Seat bolt on my bike is certainly prone to rusting and seizing up, don't know whether that's due to sweat or the conditions I ride in but I avoid it by removing, cleaning and greasing on a regular basis.

Suggestions:
- check your bolts for rust, anything that looks like it's starting to rust should at a minimum be cleaned and greased, or even better replaced with a higher quality stainless or titanium bolt
- Don't spray your bike down with water, clean it with something like Muc-Off spray and a rag. If you're spraying it (especially if you're using a pressure hose) you can be getting water into parts of the bike that it may not otherwise reach and where it may not dry out easily
- After cleaning, spray your bike with some kind of bike protection spray. These drive out moisture, provide a bit of lubrication, and leave a protective residue on the bike without leaving it sticky. Be careful about getting it on tires or braking surface though...
- Cover your headset when riding indoors
- no idea what you're talking about with the helmet, no magnets on any of my helmets, is it an MTB helmet or something? Certainly can't imagine that the shell of the helmet is getting damaged by sweat, if it's the pads/straps then these can usually be replaced. Maybe worth rinsing out your helmet with clean water after a ride, and making sure it's dry before using it again (get 2 helmets if you ride every day and there's not enough drying time between rides)

Not sure how much you can do about the corrosiveness of your sweat. Drink more water? Cut down the electrolytes? I've never used an electrolyte tab in my life, have you had gut problems when you don't use them?

Bike protection spray? Do you spray the entire bike, or just the metal places where fluid could rust the metal? The spray down makes sense. No more hose baths. As for bolts, I usually spray WD40 onto a rag, then rub the bigger bolts down. I lube the chain every other ride, but always notice rust beginning to develop between applications.

I have a Giro Air Attack and the magnets on the visor and the contact points have disintegrated. They just replaced the helmet b/c the contact points (on helmet) broke through the out shell of the helmet. My aero helmet is fine...it doesn't have exposed metal parts and I don't use it all that often.

DSW, I drink a ton of water...I prob don't need the electrolytes, but I only use them during races and longer rides. Maybe I'll just do away with them totally.

After having some similar issues with the headset fusing, I've been doing a quick wipe down with lysol disinfecting wipes after each trainer ride with some success.

It's hot, humid and sweaty where I live and I sweat a lot. I use a q-tip worth of grease and put a coating on the top of stem bolts, aero-pad bolts, basically the top of bolt that is going to get repeatedly bathed in sweat over a long ride. The trainer gets a couple towels that get removed and washed right after a session as well as a sweat guard (Kurt kinetic makes one I think, mine is old). Shoes on trainer get unclipped so everything can dry. I leave the fans going on the bike for about 10 minutes after I'm done just to dry stuff up. I buy backup sweat pads for my helmet and change them out as needed but mine doesn't have magnets so I've got nothing for ya there.

I take the bike in a couple times a year for a once-over by the bike shop guys to replace rusted parts, regrease, etc.

Some people do have higher (actually lower = more corrosive) pH levels than others. Do mosquitoes tend to stay away from you (compared to others)? If yes, it is possible - maybe even likley - that you have more acidic sweat.

Because of this I am buying a beater bike to put on my trainer.

Corrosive sweat...oh yeah. I'm in Tampa, FL and it doesn't matter whether I'm riding indoors or outdoors. For at least half the year, I rain sweat all over my bike when training outdoors. Indoors, despite a top tube cover, large towel over the front end, AC, and two fans, sweat is coming off me like a waterfall. If it's metal I will corrode it. I've fused all kinds of bolts ... even corroded then cracked one stem. Sweat seems to get into everything. One of my bikes will soon need a new crank axle from sweat/humidity/salt air getting inside the BB and corroding it.