OK, this works! My shower has never been this squeaky clean. 1 cup White vinegar heated up (microwave 1-2 min) with equal amount blue Dawn, gently shake and spray on and wait and then wipe away the soap scum. Thank you Pinterest! This is great!
I use 1 cup of vinegar and 1/2 cup of Dawn dishwashing liquid. Heat vinegar to almost a boil. Pour into a squirt bottle (empty dishwashing bottle) add Dawn and gentle mix without the lid on. Apply to shower/tub. I usually let it sit for a few minutes then wipe and rinse. You will no believe how much soap scum was there. Your shower will look brand new, even the glass doors!