The chapter is devoted to several methods of the practically important area of conservative text compression. The first eight problems concern different types of text compression: Burrows- Wheeler transform, Lempel-Ziv coding, Huffman coding and Run-length encoding. They are completely different but used in common situations. In particular there is a problem about efficient arithmetic operations on really large numbers given in their run-length encoding. In the same spirit several unrelated but interesting problems are presented about compacted automata representing all factors of special words, about pattern-matching in compressed words, about compressing suffix arrays and about the compression ratio of greedy superstrings. All these problems show how to deal with large data using compression.