No way to trim existing skillcape
As far as I and others have tested there's currently no way to trim an existing untrimmed skillcape. By software testing definition this is a defect as trimming a skillcape is a well known feature since forever.
Steps to recreate:
Buy your skillcape while you have only one 99. Get at least another 99 in some other skill. Now try to trim your first (untrimmed) skillcape somehow. Getting another 99 while wearing it or droppping and picking it do not do it.
Reported by: Benardi at Position(2690, 3425, 0)