Here is a handheld rechargeable camping showerhead that you can use anywhere to clean yourself up. The Ivation Outdoor Shower turns a bucket of water into a shower stream. The showerhead can stick to any flat surface with the provided suction cup.
You can recharge the pump with your laptop or car adapter. It lasts up to 60 minutes on a full charge. This portable shower weighs only 1.9lb and has a 6.5ft hose. You can find out more about it here.