The scratch-and-win specialist marks the keys with printed codes and covers them with a special scratch-off layer (thermochromatic or other security inks could be used).

刮奖专家以印好的编码作为标记，并在上面覆盖一层可以挂掉的特殊涂层（可以使用热变色油墨或其他安全油墨）。

youdao

They knocked off $60 because of a scratch.

因为有擦痕他们将价格降了60元。

《牛津词典》

You can scratch my name off the list.

你可以把我的名字从名单上勾掉。

《牛津词典》

Under Mr Simons' scheme, which is being implemented in Nigeria and Ghana, a scratch-off panel on the packaging reveals a code which can be texted to a special number to verify that the drugs are genuine.

ECONOMIST: Beyond voice

But for customers who want something truly special, 3x1 will create a one-off trouser completely from scratch.

FORBES: Magazine Article

Scratch off those hard to find and expensive items like Wii gaming consoles and big flat-panel screens.

FORBES: Magazine Article