Yes, that I know definitely works for mild blockages..
However, if the sink is seriously blocked, for example by strands of hair and/or grease, then pour caustic soda crystals (Sodium Hydroxide) down the plug hole and add a cupful of water. As it hits the water the caustic soda will heat it up.
Wear gloves Caustic soda will dissolve your skin, making it feel soapy at first. I remember once losing the finger prints on my fore-finger and middle finger. My fingers also really hurt!
if you do get any caustic on your skin, wash it off thoroughly, preferably in running water.

You can buy pure acetic acid in a chemists very cheaply. If you then dilute it 20 parts water to one of acetic acid you get vinegar substitute.
If you only dilute it in 10 parts of water you get amazingly strong vinegar substitite, ideal for de-greasing cookers and de-scaling kettles. However, beware the fumes! I recommend opening the kitchen window.
I used to do this in Kenya. It's an excellent home remedy/household hint.

@Petter Your chemist and American chemists often have different things available, but it is worth a try. Vinegar itself is very cheap.

@Lorajay Sometimes you can buy ready diluted 10% acetic acid under the name "industrial vinegar".

Wish I knew what a " dirt dabbler" is.

@Petter It's actually the wasp that builds it's nest from mud/dirt. I really don't know what they are named.
Mud dauber. And they are benifical to gardens in general.

@freeofgod That sounds very interesting. Pity my grandchildren are now teen-agers!

@Petter I was shocked. The baby had been to the pediatrician four times and we had used five different presription creams on her. Nothing! Within four hours of the dusting she was 100% clear.

@Petter They are beneficial in other ways and the ones in Oklahoma do not sting people. Their nests are a pain though because the red mud around my house makes a permanent stain when they use it to build a nest on my outside wall. Since I live on a lake and have an abundance of spiders, they build nests everywhere. [en.wikipedia.org]

@Lorajay , the article said spiders are the daubers favoirte thing. Especially black widows

@freeofgod @Lorajay I remember nearly 70 years ago watching the Disney film "The Living Desert" which had an impressive battle between a wasp and a spider, until the spider was anaesthetised but not killed. The wasp then laid her eggs inside the spider, as a live, non deteriorating host and source of food.
Jaw-dropping photography for its day.

@Petter I saw that every summer where I used to live. Wasps killed the green horned tomato worms everytime with that trick.