The pipe cleaner is intended to be dipped in water before installing it into the RTV-filled side cavities. RTV requires humidity to cure properly. Installation instructions within the RMB seal kit should explain this matter.

Regarding rope seals, they were originally introduced decades ago to accommodate a wide range of dimensions for the rope seal... and... those rope seals decades ago were made of asbestos (although conformable and easy to cut with a razor blade)... which has been discontinued nearly 30+ years ago from the industry. The replacement materials -- primarily which include Kevlar -- is the best material, but... extremely difficult to cut... and time-consuming to cut properly (needs a very sharp serrated blade). Rubber seals for the BB may not fit into the grooves properly due to a wide range of dimensions from a wide range of years for the BB.

I did years of testing different materials of non-asbestos rope seals when I worked for Fel-Pro as an applications engineer. We settled on a specific material that worked the best. Possibly, some other vendors are using that same/similar material, but again, not the best such as the good old asbestos material rope ... long time discontinued.