Try scrubbing with vinegar.
Sounds crazy but try vegetable oil. It works to get off price stickers so it may neutralize the chalk. Couldn't hurt the siding. Just may want to follow with a mild soap wash to remove oil.
WD40 will do same with adhesives, but this is dry chalk ( unless Kathy is mis-spelling Caulk) which is an alkali ( base) so an acid ( vinegar) would neutralize it and break the bond.
If it is actually caulk, the answer would depend on what kind it is.
True Nichter's. And also know all about mis-spells...it's called auto-correct. The bane of technology! ;)
@Marianne...LOL, I spend half my time trying to force my phone to let me spell! Awwww gets "autocorrected" to "sewers"..... and add one w and it gets auto corrected to asses....imagine the responses I get back if I'm trying to oooooh and awwwwww over someone's cute baby and they get back those resopnses instead! ..Yeah it's fun....
@ Kathy B., Nicter's has a good plan for neutralizing the chalk, but in my experience, with sidewalk chalk; after you get it all off it leaves a residue...and for that I use a paste of baking soda mixed in cooking oil until it's like silly putty....after GENTLY rubbing over the area with a soft cloth, use murphy's Oil soap to take off the cooking oil residue....
I tried the above suggestions for removing chalk on a corner vinyl piece on my porch that had been there for months. None of those worked. My mother in law came over and used toothpaste and a toothbrush. Voila! It worked!
Come on gang....so your telling this poor lady to scrub her entire vinyl home to get the oxidation off? Do you realize how long that would take her and how dangerous that would be on high ladders? Please call a professional and have it done right.
I'm own a paint company and we clean vinyl a lot. Use 1/2 cup laundry soap( I perfer liquid Tide), 2-3 cups vinger,1/4 gal. Clorox.ln a 5 gal.bucket mix ingredients and top off bucket with water up to around 4 gal. Spray on siding with graden sprayer( from bottom to top). Scrup with soft brush or use pressure washer with light pressure. Do this every spring and will keep you siding in good shape.
Very unsafe advice!!!! Mixing vinegar and bleach produces toxic chlorine gas! Irresponsible to suggest this mixture!
Most vinyl siding as it ages will begin to chalk. Even after doing a really good cleaning it does not take all that long for the film to develop again. Darker colors tend to show it up more. I have a blue home that I sided about 25 years ago and I power wash it every year and by the end of the summer it looks as though I have not touched it My fix is I have been replacing the siding a few walls at a time. Hopefully by end of year I will have newly sided home.
Clean with muriatic acid full strength and a soft scub brush. It work for me!
I did mine on house shutters!
Here is some really good info: http://joneakes.com/jons-fixit-database/1704-How-to-clean-aluminium-and-vinyl-siding