May have a different wording but what I want to know is if it is possible to remove the cement that holds tubes to the plastic? I really want to harvest these tubes.
There are two different ones I have, a dense smooth white one (ceramic texture) and a rough powdery brownish one.


If not, is there any way to trim the base without damaging the tube.

Try soaking it in a closed jar with acetone for a few days.

I have started it.
Also, I have seen some tubes have their endcaps fall off. Is this because of heat? I once saw a brand new tube have this issue, because it was kept in the sun.

I have seen at least 3 or 4 different materials (some foam-ish materials are hard, some flexible - dunno if the difference is the main resin material or just its processing/age/filler so whether to count them as one or two kind of materials, some lamps used some form of silicon), so the eventual release method will vary.
Frequent manufacturing problem is apparently glass contamination during assembly, then practically none of the materials will truly stick so very little effort is enough to free it. I doubt the sun exposure itself will be able to release it - the material is normally exposed to heat and UV from the lamp, so I would guess nothing sensitive will be used in the first place.

@Medved


The big one has a ceramic like cement. It seems to be very tightly packed and not powdery. The small one has a bumpy and powdery cement, which I could easily chip with a sharp object.

Update- I actually didn't have acetone, just dipped them in expired hand sanitizer for a day and foth came of easily!
The brown one crumpled like wet biscuits and the white one came of like clay.