This is for a rental unit, so I'm trying to keep the cost low, while also sealing it away from silverfish. I have very fine steel wool on hand as well as a tube of DAP ultra clear flexible all purpose sealant.
Regardless, I wouldn't use the sealant you have. That's a huge hole. Expandable foam could do it, but it might need to be fire rated if that's a shared or exterior wall (check local code requirements), and that might be a bigger hole than foam recommends. Also, if there's nothing behind the wall, the foam might just fall back into the void. Expandable foam also looks like shit, so if the spot is visible, do something that looks more finished.
The right way to do this would be to make the opening in the cabinet large enough to properly repair the wall. Cut a rectangular patch that fits around the pipes and secure it to studs, then spackle. If you make the gap smaller, then you could use the flexible sealant, but I still wouldn't use clear.
What's on the other side of the wall?
Regardless, I wouldn't use the sealant you have. That's a huge hole. Expandable foam could do it, but it might need to be fire rated if that's a shared or exterior wall (check local code requirements), and that might be a bigger hole than foam recommends. Also, if there's nothing behind the wall, the foam might just fall back into the void. Expandable foam also looks like shit, so if the spot is visible, do something that looks more finished.
The right way to do this would be to make the opening in the cabinet large enough to properly repair the wall. Cut a rectangular patch that fits around the pipes and secure it to studs, then spackle. If you make the gap smaller, then you could use the flexible sealant, but I still wouldn't use clear.