Suppressions exist to protect your sender reputation. Clearing them blindly is a fast path to deliverability problems.
Never clear: Spam complaints. The recipient told a mailbox provider they don't want your email. Sending again is exactly how to lose your domain reputation.
Sometimes clear: Hard bounces. If you re-acquire the address through a verifiable opt-in (new signup form completion), it's legitimate to remove the suppression.
Always clear when wrong: False positives. If a real customer complains they're not receiving emails and you find them in suppressions, check why before clearing. If the entry is incorrect (e.g., misattributed bounce), removal is fine.
Bulk clear: Almost never. If you find yourself wanting to bulk clear, you probably have a list-hygiene problem that bulk clearing won't fix.