Cậu tự tráng sạch lọ thủy tinh nhé.

(softener)

Breakdown of Cậu tự tráng sạch lọ thủy tinh nhé.

• cậu: you (informal, peer)
• tự: by oneself; self
• lọ thủy tinh: the glass jar

Questions & Answers about Cậu tự tráng sạch lọ thủy tinh nhé.

What does cậu mean here, and who can I say it to?

Cậu here means you, but it is not a neutral all-purpose you.

It is commonly used:

• between friends of similar age
• to someone younger in some family/social contexts
• in certain family relationships, where pronouns follow kinship-style rules

For a learner, the safest idea is: cậu is a fairly familiar, casual way to say you.

You should not use it with everyone. For example:

• with a stranger, it may sound too personal or wrong
• with someone older or higher-status, it may be inappropriate

So in this sentence, the speaker is talking in a familiar, not highly formal, way.

Why is there tự in the sentence?

Tự means oneself / by oneself / personally.

In this sentence, tự adds the idea that the person should do it themselves:

• Cậu tráng sạch lọ thủy tinh nhé. = Please rinse the glass jar clean.
• Cậu tự tráng sạch lọ thủy tinh nhé. = Please rinse the glass jar clean yourself.

It can imply:

• do it on your own
• don’t wait for someone else to do it
• take care of it personally

So tự adds emphasis to personal responsibility or self-action.

What exactly does tráng mean? Is it the same as rửa?