I have a crusty like hard water or white'ish lime deposit just below my water line..( from fresh water lake) you can easily scratch it off with your nail and then its smooth as glass under it..
Any ideas what to use without scewing my new paint..?
I rather buff it off at last resort..
WTF could that have been from,, on my drives too.

If it comes off that easy vinegar may do it. Otherwise Works toilet cleaner cut 50/50 with water.

Vinegar will work. Outdrive is usually the worst because the heat tends to help evaporate the water and form the deposits. Just put some in a spray bottle, spray it on and wipe with a sponge. You may have to spray it a few times. I had a bravo look chalky gray - thought I was going to have to repaint it, but I used straight vinegar and after several applications the drive looked like brand new.

White vinegar, clr or lime-away ahould work. Toilet bowl cleaner like knot 4 me said will clean very well, but strips all the wax.

I found a little hot water mixed in with the vinegar works well.

Bio-kleen hull cleaner worked amazing on exhaust tips and props for that white scale that layers on there. Just like the video says...spray, wait 5-10 and rinse. It starts foaming upon application. Very happy with the results.

Will try the vinegar and a light brush and report..fast and factual.. Thanks for the info...

Bio Kleen fiberglass cleaner works the best on scale and stainless! Far superior to anything else I have tried like vinegar, lime away, or metal waxes or polishes. No scrubbing necessary. The stuff is amazing. Get the one that says fiberglass cleaner. I don't use it on my gel only the stainless. It i will make your stainless exhaust/ steering look just like new in 5 minutes.