I've never really cleaned my pinkie plush, but I hear you can just use a sponge. And wash that way, but I don't know the accuracy of that, since I'ven never done it.
Kinda sort of new here. I joined a while back, but was pretty busy. I've been a brony since Season 5. My best ponies are:
Rainbow Dash
Pinkie Pie
Fluttershy
How's everybody? :3