May be a silly question to some of you seasoned veterans out there but not for me
Ive noticed my frame has become pretty filthy. Wasn`t really a problem before as I lived in a climate less conducive to filth. Anyhoo, what would you recommend to clean it?
Just soap and water or am I running the risk of inviting the rust demons?
Thanks in advance.

Um, rust isn't really that big of a problem unless you have a lot of blemishes in a steel/chromoly bike.

I am lazy, but anal and what I do is use a wet towel to wipe everything. Seems a lot less work then soap and water, but anything works, really. Just avoid high pressure or soaking of bearing areas: bb, headset, hubs, etc.

You can wax it using car wax or something to keep it clean longer. Works well for me. I can usually just rattle my bike around and the dried mud falls right off when I have a nice layer of wax on the bike.

Make sure to relube everything afterwards.

Good luck.

The best practice is preventative. After each ride, do a wipe down. I combine that wipe down with a jersey and shorts washing. First I get a 2 gallon bucket from Home Depot, the white one. I use laundry detergent and cold water. I soak the jersey and shorts and then proceed to use that same solution and a shop rag to wipe down the bike.

The toughest part is the down tube, the under side where all the grime attaches. I am careful here because the rubbing will scratch the paint surface. So I use a well soaked solution to remove it. Then I rinse that shop towel to get the grime off. I then wipe off again the same area to make sure all the particles are removed. The other part that gets dirty is the bottom bracket, the seat tube, the rear wheel's chain stays, and the front fork, especially in the wheel well near the crown of the fork.

The seat post sometimes gets dirty depending on the wetness of the road and how much gets splashed up there.

In about 10 minutes to 15, your bike is wiped down and now your jersey and shorts are ready for a little agitation, rinse and hang dry in the sun. That's how I remove the body sweat and odor from the clothing each time. The detergent should be enough to remove the body oils in the sweat. The sun drying makes it smell nice.

I have steel, aluminum, and carbon. So I use a automotive product like Mother's or Meguiar's detailer spray on thing. I don't know if it qualifies as a wax but it goes on fast and makes the surfaces shine and slippery.

It's not really a big deal.

When I was doing a lot of mountain biking I used to hang my muddy bikes by the saddle and clean them with a hose and sponge. I still do that once in a while, especially the ones that I ride on the limestone katy trail. I've never had a lick of trouble with rust or washing the grease out of my bearings.

I live in the midwest and have an indoor, low humidity space for bike storage. YMMV.

Soap and water. Personally, I like Dawn dishwashing detergent. I don't know if it's available in Japan.

Some ball players think that it's bad luck to clean the pine tar off of their batting helmets. I follow their example.