エンチャント
あなたがインスタント・呪文かソーサリー・呪文を1つ唱えるたび、調査を行う。(「

, このアーティファクトを生け贄に捧げる:カードを1枚引く。」を持つ無色の手掛かり・アーティファクト・トークンを1つ戦場に出す。)
Clue is an artifact type. Even though it appears on some cards with other permanent types, it's never a creature type, a land type, or anything but an artifact type.
You can't sacrifice a Clue to pay multiple costs. For example, you can't sacrifice a Clue token to activate its own ability and also to activate Alquist Proft, Master Sleuth's ability.
If an effect refers to a Clue, it means any Clue artifact, not just a Clue artifact token. For example, you can sacrifice Wrench to pay for Alquist Proft, Master Sleuth's activated ability.