I am pretty much all wfp and before that have 8 years experience trad (so prob should know the answer to this!) been doin bit of trad today, insides and when heating is on you can see all the semi circles and sharp diaganol lines left by squeegee, my technique is spot on never leave anything on the glass but its only when heating is on, have a house i do inside once a month and always have new rubber and it still shows up!
any ideas please??