It’s important to note here that you shouldn’t be tempted to use WD-40 multipurpose lubricant, because that could react with the seal and cause more problems. It must be a silicone lubricant, such as (confusingly) WD-40 Specialist High-Performance Silicone Lubricant, or Thetford Seal Lubricant. Spray silicone lubricant onto a clean cloth, rather than directly onto the rubber seals Wipe down all of the rubber seals with the silicone lubricant spray Once the liquid rubber coating is applied, it needs to cure. Though it is touch dry in only a few hours, it will take 48 to 72 hours for the coating to be fully cured and bonded to the substrate. After this point usual traffic and usage may resume. Whatever you do, don’t force it open, because you’re more than likely going to tear the seal, which would then need replacing to prevent leaks, and that isn’t a two-minute job.

Once you’ve managed to open the window and hopefully find there’s no damage, you’ll be able to proceed with essential maintenance steps.

Prepare the work area: Cover any surfaces that you do not want to get adhesive on, such as floors or nearby objects. Make sure the area is well-ventilated to prevent fumes from building up.

With everything closed again, remove the toilet cassette (this applies to both Dometic and Thetford models), so that you can begin work on it.NON-PERMEABLE– Liquid rubber paint creates an impermeable barrier between the substrate and the environment. They can withstand ponding water for flat roofs, or be used in overspill containment. They are waterproof, vapour tight, air and gas barriers. ENVIRONMENTALLY FRIENDLY– Water based and VOC free, these products will not harm you or the water table. PLASTI DIP coats and gives a comfortable, controlled, color coded grip to all types of tools; lawn and garden, mechanical, electrical, woodworking and masonry.