If your slipjoint knives are in the simple steels common to most of them, like 1095 (older USA Schrade, GEC), CV (Case), 420HC(Case, Buck), 440A (older Schrade, Camillus), 440C (GEC), etc., then you might not need anything special for compound. Green compound works very well with 1095, CV and 420HC for cleaning up burrs or polishing. And 'white rouge' (aluminum oxide) works very well with somewhat more wear-resistant stainless, like 440A, 440C, producing a polish very quickly. Personally, I think a black compound is too aggressive for most of these steels, removing metal at a much faster rate, with the potential of shortening the useful life of small traditional pocketknife blades. I don't use black compounds at all.
And for what it's worth, if you like a somewhat toothy bite coming straight off your sharpening stones, then you might not need any compound for stropping at all. If the finish work is good off the stone, most burrs can be cleaned up by stropping on simple bare leather or fabric (like denim). I don't use any compound for stropping my traditionals in 1095, CV, 420HC - instead, I just strop on the bare, sueded backside of a leather belt. With any compound, even green compound, it's pretty easy to strip all the teeth out of an edge pretty fast, with too much stropping on these steels.