The usage of etc

Question

The very popular "etc" is variously used in different situations.

I have a couple of questions concerning this abbreviation:

1. Do we need to place a full stop in the middle of a sentence after the "etc"?
2. Is it correct that "etc" can mean only similar things?

Examples:

• We have been to Ireland, Sweden, Poland, France, etc. (and other countries) where we've seen many amazing places!
• I have Pencils, Brushes, Books, CD-discs, etc. (not similar objects)

Edit: According to http://www.wikihow.com/Use-%22Etc.%22-Correctly

1. In most cases I see a full stop after "etc" in the middle of a sentence but if it means "and the rest" or "and other things" then why should there be a full stop? Also, at the end of "etc", there should be a period. (This does not apply if you are using modern "open punctuation", which dispenses with periods for eg, ie etc). What does this mean?
2. It's important that the items in the list are of the same kind so that "etc." does not confuse the reader.

Answer 1

Dictionary definitions:

etc. (also &c.) Oxford Dictionaries
short for et cetera

et cetera (also etcetera) Oxford Dictionaries
1. Used at the end of a list to indicate that further, similar items are included:
‘we're trying to resolve problems of obtaining equipment, drugs, et cetera’
1.1 Indicating that a list is too tedious or clichéd to give in full:
‘we've all got to do our duty, pull our weight, et cetera, et cetera’

etc. Cambridge Dictionary
abbreviation for et cetera: and other similar things.
It is used to avoid giving a complete list:
We saw lots of lions, tigers, elephants, etc.

To address the two questions, in the above-quoted definitions:

1. Both the Oxford & Cambridge Dictionaries show etc. as followed by a full stop (also known as a period). That is because etc. is an abbreviation for et cetera, and, in English, abbreviations are typically followed by a period in order to indicate that they are abbreviations (unless the abbreviation ends with the last letter of the un-abbreviated word). The inclusion of the period is, however, now often followed less strictly than it used to be.

2. Again, both dictionaries define et cetera as referring to similar items. If you think about it, it would be ridiculous for it to include dissimilar items because, if it did, it could refer to absolutely anything! The degree of similarity is, however, open for the writer or reader to decide or interpret.