diff --git a/lecture_material/23-clustering/README.txt b/lecture_material/23-clustering/README.txt
deleted file mode 100644
index 6ae4cc8e9c27aa0ab01800433acdf702b1a9c29d..0000000000000000000000000000000000000000
--- a/lecture_material/23-clustering/README.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-SOURCES:
- - variants.csv: https://covdb.stanford.edu/page/mutation-compare/#sars-cov-2.variants.tracking.sites
- - capital.jpg: https://en.wikipedia.org/wiki/Madison,_Wisconsin
diff --git a/lecture_material/23-clustering/variants.csv b/lecture_material/23-clustering/variants.csv
deleted file mode 100644
index c26f1f12b5cef7e8d540968603cf4adea36b1d32..0000000000000000000000000000000000000000
--- a/lecture_material/23-clustering/variants.csv
+++ /dev/null
@@ -1,63 +0,0 @@
-Variant,F 306,R 346,V 367,P 384,Q 414,K 417,N 439,N 440,Y 449,N 450,L 452,S 477,T 478,V 483,E 484,F 490,S 494,N 501,E 516
-R.1,,,,,,,,,,,,,,,K,,,,
-P.3,,,,,,,,,,,,,,,K,,,Y,
-P.2,,,,,,,,,,,,,,,K,,,,
-C.36.3,,S,,,,,,,,,R,,,,,,,,
-C.36+L452R,,,,,,,,,,,R,,,,,,,,
-C.16,,,,,,,,,,,R,,,,,,,,
-C.1.2,,,,,,,,,H,,,,,,K,,,Y,
-B.1.620,,,,,,,,,,,,N,,,K,,,,
-B.1.619,,,,,,,,K,,,,,,,K,,,,
-B.1.617.3,,,,,,,,,,,R,,,,Q,,,,
-B.1.616,,,,,,,,,,,,,,A,,,,,
-B.1.466.2,,,,,,,K,,,,,,,,,,,,
-B.1.429,,,,,,,,,,,R,,,,,,,,
-B.1.427,,,,,,,,,,,R,,,,,,,,
-B.1.214.2,,,,,K,,,,,K,,,,,,,,,
-B.1.1.519,,,,,,,,,,,,,K,,,,,,
-B.1.1.318,,,,,,,,,,,,,,,K,,,,
-AV.1,,,,,,,K,,,,,,,,K,,,,
-AT.1,,,,,,,,,,,,,,,K,,,,
-A.28,,,,,,,,,,,,,,,,,,T,
-A.27,,,,,,,,,,,R,,,,,,,Y,
-A.23.1+E484K,,,F,,,,,,,,,,,,K,,,,
-B.1.621,,K,,,,,,,,,,,,,K,,,Y,
-C.37,,,,,,,,,,,Q,,,,,S,,,
-B.1.617.1,,,,,,,,,,,R,,,,Q,,,,
-B.1.526,,,,,,,,,,,,,,,K,,,,
-P.1.2,,,,,,T,,,,,,,,,K,,,Y,
-P.1.1,,,,,,T,,,,,,,,,K,,,Y,
-P.1+P681H,,,,,,T,,,,,,,,,K,,,Y,
-P.1,,,,,,T,,,,,,,,,K,,,Y,
-B.1.525,,,,,,,,,,,,,,,K,,,,
-B.1.617.2+Q613H,,,,,,,,,,,R,,K,,,,,,
-B.1.617.2+K417N,,,,,,N,,,,,R,,K,,,,,,
-B.1.617.2+E484Q,,,,,,,,,,,R,,K,,Q,,,,
-B.1.617.2,,,,,,,,,,,R,,K,,,,,,
-AY.9,,,,,,,,,,,R,,K,,,,,,
-AY.8,,,,,,,,,,,R,,K,,,,,,
-AY.7,,,,,,,,,,,R,,K,,,,,,
-AY.6,,,,,,,,,,,R,,K,,,,,,
-AY.5,,,,,,,,,,,R,,K,,,,,,
-AY.4,,,,,,,,,,,R,,K,,,,,,
-AY.3,,,,,,,,,,,R,,K,,,,,,
-AY.2,,,,,,N,,,,,R,,K,,,,,,
-AY.12,,,,,,,,,,,R,,K,,,,,,
-AY.11,,,,,,,,,,,R,,K,,,,,,
-AY.10,,,,,,,,,,,R,,,,,,,,
-AY.1,,,,,,N,,,,,R,,K,,,,,,
-B.1.351.3,,,,,,N,,,,,,,,,K,,,Y,
-B.1.351.2,,,,,,N,,,,,,,,,K,,,Y,
-B.1.351+P384L,,,,L,,N,,,,,,,,,K,,,Y,
-B.1.351+L18F,,,,,,N,,,,,,,,,K,,,Y,
-B.1.351+E516Q,,,,,,N,,,,,,,,,K,,,Y,Q
-B.1.351,,,,,,N,,,,,,,,,K,,,Y,
-Q.4,,,,,,,,,,,,,,,,,,Y,
-Q.3,,,,,,,,,,,,,,,,,,Y,
-Q.2,,,,,,,,,,,,,,,,,,Y,
-Q.1,,,,,,,,,,,,,,,,,,Y,
-B.1.1.7+S494P,,,,,,,,,,,,,,,,,P,Y,
-B.1.1.7+L452R,,,,,,,,,,,R,,,,,,,Y,
-B.1.1.7+E484K,,,,,,,,,,,,,,,K,,,Y,
-B.1.1.7,,,,,,,,,,,,,,,,,,Y,
-B.1.1.523,L,,,,,,,,,,,,,,K,,P,,
\ No newline at end of file