If you can't find a convenient place but are desperate for getting the salt off without damage, you can try the cold weather DIY wash trick (for those of us in frozen climes):
- Find one of the places where you use a "wand" sprayer, bring lots of quarters...
- Bring your bucket-o-sudz (warm, not hot water if you can - for happy hands but no cracked glass
)
- Spray down the car using the "rinse" setting - water only (no soap, etc. selected), let it run a little before spraying your car (to let out the wheel cleaner in the pipes from the last guy)
- Now all the grit is off, do a quick once over with the soap from your bucket
- Rinse again with wand (6 more quarters!)
Go drive your car fast to dry it
, or use a water blade to get most of it off before your hands freeze...
You end up with a clean car, no brush scratches/damage, but just a little less perfect than you'd do otherwise if your hands weren't frozen solid...
Lived in apartments w/out hose access for years and this served me well.
PS: Whatever you do, don't be tempted to use the spray wax - your soft top could end up a real mess! If wax is a must then that might be the time to drive a little further and get the hand detail job...