Meaning:

“洗” means to “wash,” “客” means “clients,” and “盘” in this context is short for “楼盘,” which means “housing estates.” Two jargons used by Chinese realtors, the two terms respectively mean to “call potential buyers” and “call potential sellers” of apartments, as the verb “洗” here is used in the same sense as to “sieve.” Chinese people living in cities like Shenzhen often receive phone calls from insurance salespersons and realtors, who try to seize every opportunity to do business. These people are able to make the phone calls partly due to the easy accessibility of personal information online.

Example:

A: 今天你洗客洗盘了吗？

Jīntiān nǐ xǐkè xǐpán le ma?

Did you call potential buyers and sellers today?

B: 一早就打了好多电话，没有一个想买房卖房的。

Yīzǎo jìu dǎ le hǎoduō diànhuà, méiyǒu yīgè xiǎng mǎifáng màifáng de。

I made many phone calls this morning, but no one was interested in buying or selling an apartment.

A: 继续努力吧。

Jìxù nǔlì ba。

Just keep up your efforts.