By its very nature, backpacking is a dirty sport. You hike in dirt, cook in dirt, eat a little dirt, sleep in dirt and become coated with dirt. After a few days of trail dust, insects, insect repellent, sunscreen and sweat, you are dirty. What you long for is an exterior cleansing akin to the one natural beauty is providing for your soul.
The bears, beavers and birds do it, so can you do it too? You certainly can and there is no good reason not to bathe and play in backcountry lakes and streams if it is done right.
Like real estate, the three most important considerations are location, location and location. Choose well and you will be rewarded and refreshed; choose poorly and you may be frozen, bitten, embarrassed or any combination thereof.
For maximum enjoyment, locale considerations should include water, sun, wind protection and privacy. The lucky hiker who manages to optimize these will be a clean and happy hiker.
Water tumbles and flows through the backcountry in ways that just invite dipping. Falls, streams, lakes, ponds and pools have all been found serviceable by someone who had reached the tolerance threshold of dirty. Be common sense safe; no pools above falls or adjacent to ripping currents.
Like baptism, some prefer sprinkling and others go for total immersion. Individual tolerance to water temperature has a direct effect on bathing style and there are choices out there to suit everyone. Polar bears will find no shortage of deep cold holes to frolic in. Those of us who fear cardiac arrest can use the less traumatic wade in and splash off method. Resourceful hedonists who search out solar heated shallows and sun baked pools will be warmly rewarded for their efforts.
Commercial "solar showers" heat water for those who can't quite handle the natural product, but the contraptions have to be carted along. Try instead to concoct late season showers from waterfalls whose flow has shrunk to the rate of your water saver shower head. It may not be hot, but there is nothing to carry and no waiting.
There is a variation on the solar shower theme that is praised highly by my wife. Bring a one liter plastic soda or mineral water bottle (these are kind of bulky but weigh zero) along on your next trip. If you set up camp early, or on a layover day, fill the bottle with water and put it inside your tent. By late afternoon, the water should be warm. It may even be down right hot, depending on the day's sun/cloud cover ratio. Test it before dumping it over your head.
No matter how warm the sun feels when you are dressed and dry, it won't when you are naked, wet and standing in the wind. Remember the wind chill factor? Even a mild breeze will kick up the goose bumps. Shoot for a spot that lets the sun shine in while blocking the wind's path through.
Fair skinned folks beware; while drip drying draped over a rock or sprawled in a meadow is standard practice, don't sunbathe bare too long. The fierce high altitude sun will turn those pale bottoms and tops rosy red in short order.
Privacy is a prerequisite to pleasurable backcountry bathing. Fortunately, it's not difficult to find even in crowded areas. Map perusal will reveal suitable sites where few venture for the simple reason that there are no trails. Your perfect pool may be waiting in that seldom traveled side canyon or a short walk upstream from a busy crossing. And the likelihood of an audience decreases dramatically the further into the backcountry you go.
Consider how private your spot really is when deciding whether to bathe partially clothed or au naturel. There are places for both persuasions and you should diligently try not to be the cause of or victim of embarrassment.
Natural hot springs can restore a trail weary body like nothing else. Map study and local inquiry will alert you to the potential availability of delightful dipping spas. These should not be passed up.
Water is the universal solvent, readily relieving your body of trail grime with no help from Proctor and Gamble. Soap is not necessary to the enjoyment of a cleansing backcountry bath. Lathering up with anything in lake or stream is unthinkable and that also goes for products touted to be biodegradable. This prohibition is not as obvious as it sounds. I once foolishly left a greenhorn companion unattended and returned to find him sudsed up in the lake.
If you insist on soap, use it at least 100 feet from any water source. That requires the chore of carting wash and rinse water to your bathing spot and making sure none of it gets away, just as you do with dishwater.
One concession to chemistry you might consider is deodorant. A travel size container might be just the ticket to more harmonious hiking, particularly between tent mates.
Backpacker, bathe thyself! The bears, beavers and birds don't mind sharing the facilities as long as you don't sully the tub.