I am having a difficult time picturing your exact issue. I am aware of butyl tape behind the window frame flange to seal against the fibreglass, but I am unsure of butyl tape that would be near the EPDM roof of the slide, or under your bedroom slide.
The slide seals are all around the slide, but I am pretty sure they are not butyl tape, they are a rubber compound buy not continually sticky. My slide seals left marks when new but these marks wiped off easily and stopped fairly quickly after using the slides a number of times (dust from road travel, camping etc) - but I digress.
Excess butyl tape around windows can be removed carefully with a plastic scraper, and cleaned up with goo gone or other similar products, be prepared to re-polish with Gel-Gloss or similar as Goo Gone removes wax as well. Do not use Goo Gone or any petroleum based solvents on EPDM. Dicors web site
[link] helps a lot with cleaning maintenance tips for EPDM. THere are a few other threads here that discuss this issue (the search function will help).
Hope this is what you were looking for.
Take care,
Brian