Hi and welcome Mr. Loco! :hi:
Personally I´m always a bit cautious with displaying glass on a sunny window sill although it´s such a fascinating
thing to see your items in the different lighting situations.
For the following reasons:
- clear glass can change the colour over the time. Some glass becomes slightly yellowish or greenish and over a
longer period purple-is; I´m not sure about the first two effects, but the latter is caused by the manganese
content in the glass batch.
- some glasses can work as a lense - especially paperweights - and even cause burning. I think we´ve got a topic
about an article in some newspaper some time ago.
- the heating when exposed to the sun can cause stress fractures, if the annealing wasn´t sufficient or there
are still strains within the glass. Bubbly items are even more endangered because of the different extension
levels of glass and air.
I therefore tend to keep my better pieces north and some of the minor and coloured ones south...
Surely others will be adding quite a bit to your thread.