I’m curious if it’s possible to initiate with someone who may not want to clear?
Having been hurt by someone is one of the most vulnerable experiences a person can have in their lifetime. Being hurt by someone has many layers. First, the thing that happened doesn't feel good nor safe and how do I know it's not going to happen again. Second, the hurt is often bringing up older hurts. Often, it's hard to distinguish between the hurt right now and the hurt from the past. It's also scary to hear what the other person might say about what happened. What if it hurts more?
You can look at this problem as a consent issue. If they are a "no" to clearing, then honoring that boundary is key to them feeling safe to do so at some point (even if it's far into the future).
Keeping the door open and letting them know (gently) that you'd like to clear with them (even if it's far in the future) is key. Sometimes the invitation can come in a spontaneous moment you run into them and being ready with what you might say would be a good idea. Making sure your invitation is a request and not a demand is also key (let me know if you need further explanation about the distinction).
I'd also say being in touch with your "why" can help create a bridge to their yes. Exploring the layers of why you want to clear with them will help you name to them why they might get inspired to clear with you. Ask yourself over and over again, "why". If you can tell someone why it might benefit them too to have a clearing with you then they might feel safe enough and inspired enough to say yes.