DECALDEF animator clean

I was editing the DECALDEF for some monsters from Realm 667, and I saw that several of them are using animator clean, but that animator is not defined anywhere. I looked in Zandronum.pk3 and ZDoom.pk3 and GZDoom.pk3 and their DECALDEF lumps do not include the word clean. I also searched the ZDoom Wiki. I know how to use DECALDEF, but I have ever heard of an animator named clean, and I cannot find a definition for it anywhere. I am guessing it is a fader, but I don't know the settings, nor why they didn't use GoAway or GoAway2, or include the definition of the non-standard animator that they are using.

Can anybody find the definition for the animator named clean, or should I just edit it to use GoAway instead?

Here are links to the monsters, and it turns out to be only two monsters with multiple decals each:

Phase Imp: https://realm667.com/index.php/en/component/docman/?task=doc_download&gid=178&Itemid=
Incubus: https://realm667.com/index.php/en/component/docman/?task=doc_download&gid=149&Itemid=

I decided to replace the undefined Clean animator with GoAway3, which I was already using for other decals, and which I defined as follows:

fader GoAway3
{
    DecayStart    5.0
    DecayTime    5.0
}