she never heard of dry cleaning issit?

Lel. It's expensive but it's meant for expensive dress / suit etc. I don't know whether normal dobi have them because I don't have super expensive clothes but if you do have one, you need to dry clean them.

Last year I sent something for dry cleaning, the price was within RM 10 ish, maybe slightly more, but that's for suit. Dress IDK.

You can hand wash. My fiancee has a few dinner dresses. She handwash. If you don't want the colors to fade, use only cold water and don't put too much detergent coz it'll kill the colours. I know because I always help her wash them. Girls got fingernails, so it make spoil them a bit. So it's the man's job.

Chiffon clothes, warm or cold is ok. For satin and silk, never use warm, only cold. This is because overtime, silk/satin will lose it shinyness. Chiffon, depends. My fiancee has a chiffon-mixed-satin skirt. We only use cold waters.

Based on the pictures given, those are chiffon materials. Handwash them is fine, won't spoil. You can trust me coz I'm the one washing my fiancee's dinner dresses. If possible, after washing, let it drip. Don't twist and turn the clothes. Definitely spoil. And never dry under direct sun light. Dry under a shade. With heat also can dry.