Finally.

After been trying all tips I found and given up several times during the years. I today found a way of removing the grills inspired by this thread. I used the back end of a spoon with a very smooth shape. Over the spoon end I mounted self-adhesive velour. The velour made sure that:

1. No marks were done on the cloth
2. The spoon did not slip during the process

Using both hands over the spoon and the thumbs on the cabinet the grills came of with some effort.

(My first "sucess" was done using the spoon without the velour mounted, this resulted in glossy marks on the fabric and a cracked grill ring.)

The screws could be tighten between 1/4 to 0 turns.


Holodeck 2: DSP5k2SE+7k2HCSE, DSP33, G68J, 621, DD15, OPPO-203, VW790, ST130G3-120", TSU-9400/RFX-9600, PS4, SB3, Buttkicker-XL (DIY JL 12W7)
In Kitchen: P200Z, T-amp, Equalizer, SB2