slightly pushed in softdome tweeter on Fritz speaker

I've successfully used a vacuum nozzle.... carefully.  Guide the nozzle keeping it away from the tweeter so as not to create a damaging suction.  Some vacuums allow selection of weaker suction power.  It''s like fielding a pop-up fly, use BOTH hands.

Might sound weird, but how about a turkey baster? Just pop the squeeze bulb off the end and gently place that end over the dome while sucking on the small end. Same as the vacuum cleaner suggestion but a whole lot gentler and easier to control. 

This is exactly why I made slide-over speaker boxes from black matboard material for my Sonus Faber Sonetto V G2. I just slide them up and off to play and slide back over when done listening. They have saved the day from sweepers or knees, etc in tight entry way.

I hope I am not sounding rude but how about giving Fritz Heiler a call. After all, he made the thing. Will it affect the sound? Will it? Listen to it and tell us what you think. You have the fruit in your hand, tell US how it tastes my friend. 

I have used a pin or needle to pull out dust covers. Works well with fabric dust covers, I think it would work on a soft dome without leaving a mark. It's not necessary to push the pin through the membrane but more of a side stab and pluck.