What would you do?

This happens quite a lot with me. The other day, 2 colleagues (quite senior to me) of mine were discussing a configuration problem at work. They were in the cubicle adjoining to mine and I could hear them quite clearly. It so happened that I had previously worked on a similar issue with successful results. What you have done in this situation? Butt in their conversation and tell them - "Hey guys, you know what I have done this before, allow me to show you how" or would you keep to yourself and think"Oh! that is not a big deal, they will figure it out in no time"? Call me timid or shy or whatever but I just could not get myself to do the former. Well, I have done something on those lines before - but when only the matter of concern is something in which I have a reasonable amount of knowledge and / or expertise not something I have done in passing. Would it have mattered if they were not seniors but my peers? I think so, yes. But that's just me.